MRD Monitoring Reveals a Specific Biology of BCR/ABL-Positive ALL

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2529-2529
Author(s):  
Marketa Zaliova ◽  
Leona Reznickova ◽  
Eva Fronkova ◽  
Katerina Krejcikova ◽  
Katerina Muzikova ◽  
...  
Keyword(s):  
Residual Disease ◽  
Fusion Gene ◽  
Fusion Transcript ◽  
Cell Receptor ◽  
Quantitative Detection ◽  
Gene Transcript ◽  
Equal Distribution ◽  
Childhood All ◽  
Negative Results

Abstract Minimal residual disease (MRD) monitoring is an essential tool for current leukaemia therapy. The only standard method for MRD monitoring in childhood ALL is the quantitative detection of clonal immunoglobulin (Ig) and T-cell receptor (TCR) genes rearrangements. The quantitative detection of fusion genes or transcripts provides an alternative option for MRD monitoring. We aimed to compare the significance of these MRD methods by parallel monitoring of fusion transcripts/genes and Ig/TCR targets during the follow-up of children from the three most common ALL genotype groups. We analysed 117, 109 and 191 bone marrow samples from 28 TEL/AML1-positive, 7 MLL fusion-positive and 16 BCR/ABL-positive patients, respectively. To keep the comparability of different MRD approaches, we used qPCR detection systems with similar sensitivity (at least 10−4), we adopted ESG-MRD-ALL principles for MRD quantification and we related the MRD level in follow-up samples to the diagnostic level for all MRD methods. We found a very good correlation of fusion transcript- and Ig/TCR-based approaches (R2=0.903) with only 7% of samples differing by more than 1 log in a cohort of TEL/AML1-positive patients. A good correlation was also found between fusion transcript- and Ig/TCR-based MRD in MLL fusion-positive patients (R2=0.8419). Only 10% of samples differed by more than 1 log, being underestimated by Ig/TCR in 4.5% and by MLL-fusion transcript in 5.5%. For the follow-up of MLL-fusion-positive patients we further employed the monitoring of MLL-fusions on genomic level. The MRD based on genomic MLLfusion genes showed a very good correlation with Ig/TCR -based method (R2=0.9124) with only 5% of samples differing by more than 1 log, and it also closely correlated with MLL-fusion transcript levels (R2=0.9195). Strikingly, in BCR/ABL-positive patients we found a limited correlation of fusion transcript-based and Ig/TCR-based MRD (R2=0.6880) with 1/3 (34%) of samples differing by more than 1 log. In contrast to the MLL cases, the underestimation of MRD by individual methods was “asymmetrical”: 8% of the discordant samples had higher MRD measured by Ig/TCR and 26% by BCR/ABL transcript. Despite identical sensitivity of both methods, in 19% of samples the MRD positivity was revealed only by BCR/ABL approach while Ig/TCR approach gave negative results. Detailed analysis showed clinical significance of the discordant BCR/ABL vs. Ig/TCR MRD information. Altogether, 13 relapses occurred during the follow-up of our cohort. We compared number of BCR/ABL and Ig/TCR -positive samples among all BM specimens taken 6 and 12 months before relapse. While the majority of samples preceding relapse were BCR/ABL-positive (14/18 and 22/36 six and twelve months before relapse) only a minority of samples showed Ig/TCR positivity (7/18 and 12/36, respectively). The non-equal distribution of the BCR/ABL and Ig/TCR-positive samples was statistically significant (p=0.04 and p=0.03 for the two time-points, respectively). Our study shows, that in TEL/AML1 and MLL fusion-positive patients, fusion gene/transcript-based MRD monitoring provides information highly concordant to the standard Ig/TCR approach and thus it is useful as a complementary method in patients with absent or inadequate Ig/TCR targets (particularly in MLL cases where clonal Ig/TCR rearrangements are rare). The situation is different in BCR/ABL patients, where the MRD information from both approaches is discordant in a high subset of samples. This result probably reflects the dissimilar biology of this ALL subtype and the fact, that BCR/ABL-positive (prae-)leukaemic stem cell is different and multilineage involvement more common. Thus, in some cases, the fusion transcript monitoring reveals the existing pool of cells that increase the risk of relapse despite the Ig/TCR negativity. We conclude that MRD in all BCR/ABL–positive patients should be monitored not only by the standard Ig/TCR approach but in parallel also by the quantitative fusion transcript-based detection. Support: MSM0021620813, MZO00064203.

Limited Reliability of Ig/TCR Based MRD Monitoring in BCR/ABL-Positive Childhood ALL: Comparison to Quantitative Fusion Transcript Detection.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2340-2340
Author(s):  
Katerina Krejcikova ◽  
Katerina Muzikova ◽  
Eva Fronkova ◽  
Marketa Kalinova ◽  
Leona Reznickova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Fusion Gene ◽  
False Negative ◽  
Fusion Transcript ◽  
Childhood All ◽  
Expression Levels ◽  
Diagnostic Samples ◽  
Transcript Detection

Abstract Leukemias with the t(9;22) translocation resulting in BCR/ABL fusion protein expression comprise 3–5% of childhood ALL. Despite modern therapeutic regimens, their prognosis is inferior. Minimal residual disease (MRD) based on leukemia-specific immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements has become a tool influencing clinical decisions in many therapeutic trials for childhood ALL. The presence of BCR/ABL fusion gene offers a possibility of the fusion transcript detection - a faster and cheaper alternative to Ig/TCR-based MRD monitoring. Up to now, no direct comparison based on a sufficient number of samples has been done. We analyzed 350 follow-up samples from 16 children (aged 4–17 years) with BCR/ABL-positive ALL by Ig/TCR-based real-time quantitative PCR (RQ-PCR) and by reverse-transcriptase (RT) RQ-PCR for BCR/ABL transcripts. Beta-2 microglobulin housekeeping gene was used for cDNA quality normalization. WBC, age, immunophenotype and blast proportion in the bone marrow (BM) and peripheral blood (PB) showed no relation to the initial BCR/ABL level. All children expressed m-BCR/ABL transcript at the time of diagnosis; 3 of 16 children expressed both m-BCR/ABL and M-BCR/ABL transcripts representing the p190 and p210 variant of BCR/ABL protein, respectively. The expression levels of m-BCR/ABL in diagnostic samples differed up to 3 logs, being the lowest in patients expressing both variants of the fusion gene. In 38 samples from those patients, M-BCR/ABL expression was generally higher than m-BCR/ABL expression, being negative by m-BCR/ABL and positive by M-BCR/ABL in 13 samples. For further analysis we used the higher value of m- and M-BCR/ABL as the BCR/ABL MRD level. For the comparison with Ig/TCR-based method, MRD levels in follow-up samples were related to the expression levels in diagnostic samples, which were set to 1. In total, 133 (38%) and 127 (36%) samples were negative and positive by both methods, respectively. The quantitative levels differed by more than 1 log in 46 (36%) double-positive samples, being underestimated by Ig/TCR method in 25 cases and by m-BCR/ABL quantification in 21 cases. With the same sensitivity of both methods we found significantly more false-negative samples by Ig/TCR approach (70 samples) compared to BCR/ABL quantification (20 samples). Altogether, we tested 219 bone marrow (BM), 130 peripheral blood (PB) and 1 cerebrospinal fluid samples. The PB samples showed significantly worse correlation between the two methods compared to BM (p=0.02). Interestingly, some patients had higher MRD levels in PB compared to BM as shown by corresponding BM and PB samples. Our data suggest that BCR/ABL-positive childhood ALL is a biologically heterogeneous group. We show that all diagnostic samples should be screened for the simultaneous m- and M- BCR/ABL expression to avoid false-negativity when using m-BCR/ABL quantification only. In our hands, the quantification of BCR/ABL transcripts appears to be a more reliable method than the generally accepted Ig/TCR-based MRD monitoring as the number of false-negative samples by BCR/ABL quantification is significantly lower. This contention is further supported by our pilot data on transplanted patients where BCR/ABL positivity preceding transplantation seems to be a better predictor of subsequent relapse than Ig/TCR approach. Support: MSM0021620813, MZ00064203 and 62/2004 GAUK CR. KK and KM contributed equally to this work.

scholarly journals Variable but Consistent Pattern of Meningioma 1 Gene (MN1) Expression in Different Genetic Subsets of Acute Myelogenous Leukaemia and Its Potential Use as Marker for Minimal Residual Disease Detection.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3494-3494
Author(s):  
Daniela Cilloni ◽  
Francesca Arruga ◽  
Francesca Messa ◽  
Sonia Carturan ◽  
Enrico Bracco ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Minimal Residual Disease ◽  
Residual Disease ◽  
Fusion Gene ◽  
Gene Overexpression ◽  
Disease Detection ◽  
Gene Transcript ◽  
Minimal Residual Disease Detection ◽  
Minimal Residual

Abstract Meningioma 1 (MN1) gene overexpression has been reported in acute myeloid leukaemia (AML) patients and identified as a negative prognostic factor. In order to characterize the patients presenting the gene overexpression and to verify if MN1 transcript could be a useful marker for minimal residual disease detection, MN1 has been quantified by RQ-PCR in 136 AML patients of different cytogenetic groups and in 50 normal controls. In 20 patients bearing a fusion gene transcript (FG) suitable for MRD assessment, we performed a simultaneous analysis of the MN1 and of the FG transcript during follow-up. Sequential MN1 and WT1 analysis was also performed in 10 AML patients lacking other molecular markers. The MN1 levels were extremely low in normal samples: the median of 2−ΔΔCt is 4,6 ±2,9 (range 3–10) in PB and 16 ±19,6 (range 6–50) in BM and 12,9 ±4,8 (range 11–19) in normal CD34+ cells. Conversely, about 50% of the AML samples with normal karyotype (NK) showed high expression of the MN1 gene with a median value of 2−ΔΔCt =111±590 (range 52–2352) in BM and 101± 399 (range 12–1136) in PB. All samples carrying the CBFβ-MYH11 FG expressed a significantly higher amount of MN1 transcript as compared to controls (p<0,0001 in both BM and PB): median =1176±1180 (range 362–2272) in BM and 588±401 (range 17–1060) in PB. About 50% of the samples with AML1-ETO FG abnormally expressed MN1: median of 89±58 (range 55–181) in BM and 54±29 (range 21–81) in PB. Finally, the APL samples expressed MN1 values comparable to those of healthy subjects in both BM (p= 0,05) and PB (p=0,08). Interestingly, the paired analysis established a remarkable correlation between MN1 expression in PB and BM with a r value of 0,9627. Stratification of patients according to the presence of FLT3 mutation or ITD demonstrated no significant association between the two abnormalities. In contrast, MN1 overexpression is typically present in patients with mutations in NPM1. 36 out of 47 patients presenting NPM1 mutations were characterized by abnormal expression of MN1. Finally, we were unable to find any significant correlation between EVI-1 and MN1 expression (r= 0,06). To assess the significance of MN1 as a marker for MRD detection in AML, the MN1 transcript was quantified during follow-up of 20 AML patients characterized by the presence of FG (15 CBFβ-MYH11 and 5 AML1-ETO) and 10 patients lacking additional markers monitored by WT1 quantitative assessment, In all cases characterized by FG transcript, the longitudinal pattern of MN1 expression always paralleled that of the FG. Furthermore, MN1 strictly paralleled WT1 in patients without any FG. In all the cases MN1 rose at least two months before relapse. In conclusion, the data obtained show that high levels of MN1 expression are present in 47% of patients with NK primarily in those with wild type NPM1, and in all cases with inv(16). The MN1 levels during follow-up were found to follow the pattern of the other molecular markers (fusion gene transcripts and WT1). Increased MN1 expression in the BM during follow up was always found to be predictive of an impending hematological relapse.

How I treat chronic lymphocytic leukemia after venetoclax

Blood ◽  
2021 ◽  
Author(s):  
Thomas E Lew ◽  
Constantine S. Tam ◽  
John F. Seymour
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Residual Disease ◽  
Treatment Options ◽  
Cell Receptor ◽  
Resistance Mechanisms ◽  
Lymphocytic Leukemia ◽  
Bcl2 Family ◽  
Clinical Scenarios ◽  
Car T

Venetoclax-based regimens have expanded the therapeutic options for patients with chronic lymphocytic leukemia (CLL), frequently achieving remissions with undetectable measurable residual disease (uMRD) and facilitating time-limited treatment without utilizing chemotherapy. Although response rates are high and durable disease control is common, longer-term follow-up of patients with relapsed and refractory (RR) disease, especially in the presence of TP53 aberrations, demonstrates frequent disease resistance and progression. Although the understanding of venetoclax resistance remains incomplete, progressive disease (PD) is typified by oligoclonal leukemic populations with distinct resistance mechanisms, including BCL2 mutations, upregulation of alternative BCL2 family proteins and genomic instability. Although most commonly observed in heavily pre-treated patients with disease refractory to fludarabine and harboring complex karyotype (CK), Richter transformation (RT) presents a distinct and challenging manifestation of venetoclax resistance. For patients with progressive CLL after venetoclax, treatment options include B-cell receptor pathway inhibitors (BCRis), allogeneic stem cell transplantation (SCT), chimeric antigen receptor (CAR) T-cells, and venetoclax re-treatment for those with disease relapsing after time-limited therapy. However, data to inform clinical decisions for these patients are limited. We review the biology of venetoclax resistance and outline an approach to the common clinical scenarios encountered after venetoclax-based therapy that will increasingly confront practising clinicians.

Co-Existence of Various Sub-Clones in TEL-AML1 Positive Acute Lymphoblastic Leukemia in Association with Sub-Microscopic Deletion of AML1.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1096-1096
Author(s):  
Amos Toren ◽  
Rachel Rothman ◽  
Bella Bielorai ◽  
Malka Reichart ◽  
Ninette Amariglio ◽  
...  
Keyword(s):  
Minimal Residual Disease ◽  
Gene Rearrangement ◽  
Chromosomal Abnormalities ◽  
Residual Disease ◽  
Fusion Gene ◽  
Lymphoblastic Leukemia ◽  
Prognostic Significance ◽  
Submicroscopic Deletion ◽  
Minimal Residual

Abstract The TEL/AML1 fusion gene is the most common gene rearrangement in pediatric acute lymphoblastic leukemia (ALL). Although considered to be a low risk leukemia it has a 20% risk of late relapse. The coexistence of different sub clones at diagnosis, based on polymerase chain reaction (PCR) studies of Ig/TCR gene rearrangement, was recently reported in this subtype of ALL. Their different response to chemotherapy may explain the emergence of certain sub clones at relapse, and may serve as a marker for minimal residual disease follow-up. Several chromosomal rearrangements such as t(9;22), t(8;21), inv(16) and rearrangements of the MLL gene are frequently associated with submicroscopic deletions and some of them have prognostic significance. Such deletions were not reported in t(12;21) positive ALL. Bone marrow cells from 76 pediatric patients with ALL at diagnosis were analyzed for the presence of the TEL/AML1 fusion gene by interphase fluorescence in situ hybridization (FISH). We used a new system of combined analysis enabling a very large-scale study of the cells of interest with regard to morphology, FISH and immunophenotyping. Fourteen patients were positive for the translocation. Four of them had several sub clones associated with various combinations of additional chromosomal abnormalities. The most striking was an atypical and unexpected hybridization pattern consistent with a submicroscopic deletion of the 5′ region of the AML1 breakpoint (intron2) not previously reported. We describe the use of a larger probe for AML1 (AML1/ETO) to exclude the possibility of insertion of TEL into the AML1 region without breakage and to reduce the false positivity due to optical fusion. This may enable a better monitoring of minimal residual disease in cases with submicroscopic deletion. All patients had some sub-clones with TEL deletion. Other abnormalities included trisomy and tetrasomy 21 as well as double TEL-AML1 fusion. The analysis of numerous sub-clones at presentation in these patients suggests clonal evolution at an early stage of the disease. These sub-clones may have different sensitivities to chemotherapy, and some of them may reappear at relapse. The frequency of AML1 deletion in t(12;21) in addition to other chromosomal abnormalities, is unknown. The involvement of these findings in the generation of leukemic sub clones, their prognostic significance and role in minimal residual disease follow-up deserves further studies in a large number of patients and a longer follow-up.

Minimal Residual Disease (MRD) Analysis in Acute Myeloid Leukemia (AML) with Favorable Cytogenetics [t(8;21) and inv(16)] by Real Time PCR(RT-PCR) and Flow Cytometry (FC).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2989-2989
Author(s):  
Granada Perea ◽  
Adriana Lasa ◽  
Anna Aventin ◽  
Alicia Domingo ◽  
Neus Villamor ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Residual Disease ◽  
Fusion Transcript ◽  
Good Prognosis ◽  
Rt Pcr ◽  
Free Survival ◽  
End Of Treatment ◽  
The Mean ◽  
Minimal Residual

Abstract Objectives: To analyze MRD in 65 patients (pts) with good prognosis AML: 30 t(8;21) and 35 inv(16), using both FC and RT-PCR, and to investigate the prognostic value of MRD in the pts outcome. Methods: MRD was monitored in CR pts (n=55) by FC in 101 follow-up samples obtained after various cycles of treatment, as follows: 40 post-induction (ind), 30 post-intensification (int) and 31 at the end of treatment (ttm), and by RT-PCR in 76 samples: 31, 23 and 22, respectively. In 35 pts the two techniques were applied at the same time of the ttm. MRD by FC was assessed using fixed combinations of three monoclonal antibodies. AML1/ETO and CBFb/MYH11 were analyzed following the BIOMED protocol. Results: Twenty-seven percent (n=15) of CR pts relapsed: 6 with t(8;21) and 9 with inv(16). The mean MRD by FC was 1.1% after ind, 0.2% after int and 0.1% at the end of ttm. At the end of ttm, the MRD detected by FC in relapsed and not relapsed pts were significativaly different: 0.3% vs 0.08% (p=0.002). By RT-PCR, the mean of fusion transcript copies/ablx104 differed between relapsed and nonrelapsed pts: 2385 vs 122 (p=0.001) after ind, 56 vs 7.6 after int (p=0.0001) and 75 vs 3.3 (p=0.0001) at the end of ttm. Relapses were more commonly observed in those pts with FC MRD level >0.1% at the end of ttm than in pts with ≤0.1%: 50% vs 12% (p=ns); likewise, using RT-PCR, a cutoff level of >10 copies at the end of ttm correlated with high risk of relapse: 80% of pts with RT-PCR >10 relapsed compared to 12% of pts with levels <10 (p=0.009). The overall survival (OS) probability was 86% for pts with CF MRD ≤0.1 at the end of ttm and 0% for pts with MRD >0.1 (p=0.1) and the leukemia free survival (LFS) was 78% and 44%, respectively (p=0.05). For pts with RT-PCR ≤10 at the end of ttm, the OS was 100% and for pts with RT-PCR >10 it was 30% (p=0.007) and the LFS was 87% and 20%, respectively (p=0.001). MRD was identified after ind in 55% of relapsed pts and at the end of ttm in 83% of relapsed pts. Only 1 pt (1/13) with FC MRD <0.1 and RT-PCR <10 at the end of ttm relapsed. For patients in complete remission, the mean copy level of chimeric transcript was higher for pts with t(8;21) than for those with inv(16): 30.2 vs 17.4 (p=0.0001). Comments: In tandem analysis of MRD by FC and RT-PCR could improve MRD detection in AML pts.

The Repertoire of Gene Rearrangements in Acute Lymphoblastic Leukemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1464-1464
Author(s):  
Alexander A. Morley ◽  
Michael J. Brisco ◽  
Pamela J. Sykes ◽  
Sue Latham ◽  
Elizabeth Hughes ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Acute Lymphoblastic Leukemia ◽  
High Efficiency ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Cell Receptor ◽  
Gene Rearrangements ◽  
Childhood All ◽  
Repertoire Analysis ◽  
Specificity And Sensitivity

Abstract Rearrangements of the immunoglobulin and T-cell receptor genes provide molecular markers for clones in acute lymphoblastic leukemia (ALL). Determination of the repertoire of gene rearrangements in ALL aids in understanding the clonal biology of the disease and provides molecular markers which can be used to quantify minimal residual disease (MRD). We have developed a sensitive PCR-based method for analysing the repertoire of immunoglobulin heavy chain (IgH) rearrangements in ALL. Multiple parallel quantitative PCR’s are performed in microplates using different segment-specific primers in different wells in order to determine the individual V (D) and J segments utilised by each rearrangement. The number of rearrangements detected in 18 children and 10 adults with ALL is shown in the table: VDJ rearrangements DJ rearrangements No. of rearrangements 1 2 3 4 1 2 Childhood ALL 0 11 3 2 1 1 Adult ALL 7 2 0 1 Since each PCR well contained only 2 ng of DNA, more sensitive repertoire analysis was also performed in samples from 10 of the children and 4 of the adults by using 100 ng of DNA in an initial preamplification, which involved a multiplexed PCR containing primers for all leader and J sequences of the IgH gene and which thus amplified all immunoglobulin sequences. The IgH repertoire of the amplified material was then analysed. This two-step approach should theoretically enable detection of clones which comprise down to approximately 10−4 the leukemic population. It detected all rearrangements previously detected by one-step repertoire analysis and, in addition, it detected 0–5 (mean 1.2) rearrangements marking small clones in childhood ALL and 0–3 (mean 1.0) rearrangements marking small clones in adult ALL. Sequencing showed that most, but not all, small clones had a lineage relationship to the dominant clone present in the leukemic population. Repertoire analysis of IgH rearrangements is a promising technique for identifying molecular markers for measurement of MRD in B-ALL, particularly childhood ALL, since: –it is conceptually simple and relatively quick –it detects IgH rearrangements with high efficiency, probably higher than that of current techniques. –IgH rearrangements are the best markers to use for measurement of MRD owing to the specificity and sensitivity that they provide –an enhanced ability to identify markers for both large and small leukemic clones may improve the identification of patients prone to relapse.

Flow Cytometric Evaluation Of Minimal Residual Disease In Adult Acute Lymphoblastic Leukemia Using a Simplified, Single-Tube Approach

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1378-1378
Author(s):  
Roger Belizaire ◽  
Olga Pozdnyakova ◽  
Daniel J. DeAngelo ◽  
Betty Li ◽  
Karry Charest ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Turnaround Time ◽  
Tube Flow ◽  
Flow Cytometry Assay ◽  
Single Tube ◽  
Negative Results ◽  
Minimal Residual

Abstract Flow cytometry for detection of minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL) has been widely used in pediatric patients to quantify therapeutic response and to assess the risk of relapse. Flow cytometry for MRD provides roughly the same level of sensitivity (0.01%) as molecular methods but at lower cost and with faster turnaround time. MRD assessment in ALL currently requires an evaluation of 20 or more parameters divided among multiple tubes. In part due to the assessment complexity, the use of flow cytometry for MRD detection in adult ALL patients has been relatively limited. We developed a 6-color, single-tube, flow cytometry assay to detect MRD in bone marrow (BM) aspirate specimens from adult ALL patients. The 73 patients included 52 patients with B-ALL (71%), 19 patients with T-ALL (26%) and 2 patients with T/myeloid leukemia (3%) and were treated with one of several standard chemotherapeutic regimens or targeted therapies. Patients were tested for MRD by flow cytometry after induction or re-induction therapy and serially thereafter. The 6-marker MRD panel was customized for each patient based on the 18-20-marker diagnostic immunophenotype. Sixty-three percent of B-ALL patients (n=33) had lymphoblasts with an aberrant immunophenotype; expression of a myeloid marker (e.g., CD13, CD15 or CD33) was the most common aberrancy. The remaining 37% of B-ALL patients (n=19) had disease with a hematogone immunophenotype, which comprised surface expression of CD10, CD19, CD20, CD34, CD38 and CD45; in the majority of these cases, leukemic cells were distinguishable from normal hematogones based on the intensity of surface marker expression. Forty-seven percent of T-ALL patients (n=9) had an aberrant immunophenotype, most often characterized by CD33 expression. One-hundred forty-six consecutive specimens analyzed for MRD by flow cytometry were classified as positive (23%), negative (72%) or uncertain (5%). Of the 34 samples classified as positive, 14 (41%) showed morphologic (i.e., BM aspirate or biopsy) evidence of disease; nineteen (65%) samples did not show morphologic evidence of disease and 1 sample did not have a concurrent morphologic assessment. Of the 105 samples classified as negative by flow cytometry, 103 (98%) were also negative by morphology and 1 sample did not have a concurrent morphologic assessment. One sample that was negative by flow cytometry had morphologic evidence of disease in the biopsy (10-20% blasts) but not the aspirate, suggesting that aspirate sampling artifact was responsible for the discrepancy. None of the 7 samples classified as uncertain by flow cytometry had morphologic evidence of disease; five out of 7 uncertain classifications were in B-ALL patients with hematogone immunophenotypes. Overall, MRD flow cytometry showed 86% concordance with the results of morphologic assessment. We evaluated outcomes in all patients with negative morphologic results and any positive MRD flow cytometry result(s). Of the 73 patients in this study, 61 had morphology-negative results that were either MRD-negative (n=45) or MRD-positive (n=16). Patients in this group were at various points of treatment post-induction or re-induction. Four out of 45 patients (9%) with MRD-negative results relapsed during a median follow-up period of 22 months, and 8 out of 16 patients (50%) with an MRD-positive result relapsed during a median follow-up period of 15 months (odds ratio for relapse 10.3, 95% confidence interval 2.5-42.4, P=0.001). In addition, relapse-related and overall mortality (Figure 1) were higher in patients with MRD-positive results (P=0.0023 and P=0.0016, respectively, by the log-rank test). In summary, we present a simplified, single-tube, flow cytometry assay that can be used to detect MRD in adult ALL at relatively low cost with rapid turnaround time; our approach was applicable to cases with either hematogone or aberrant immunophenotype, yielding a definitive result in 95% of cases. Notably, the presence of MRD was associated with relapse and mortality, suggesting that our method of MRD assessment could be used to guide treatment of adult ALL. Further analysis of the correlations between MRD results, clinical management and patient outcomes is ongoing. Disclosures: No relevant conflicts of interest to declare.

Minimal Residual Disease Monitoring in Childhood Precursor B Lymphoblastic Leukemia with t(12;21)(p13;q22); ETV6-RUNX1: A Comparison Between Quantitative RT-PCR and Flow Cytometry

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3774-3774
Author(s):  
Sofie J Alm ◽  
Charlotte Engvall ◽  
Julia Asp ◽  
Lars Palmqvist ◽  
Jonas Abrahamsson ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Minimal Residual Disease ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Fusion Transcript ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Time Points ◽  
Qrt Pcr ◽  
Minimal Residual

Abstract The translocation t(12;21)(p13;q22) resulting in the fusion gene ETV6-RUNX1, is the most frequent gene fusion in childhood precursor B lymphoblastic leukemia (pre-B ALL), affecting about one in four children with pre-B ALL. In the NOPHO ALL-2008 treatment protocol, treatment assignment in pre-B ALL is based on clinical parameters, genetic aberrations, and results from analysis of minimal residual disease (MRD) at day 29 and 79 during treatment (where MRD >0.1% leads to upgrading of treatment). For pre-B ALL, in this protocol MRD analysis is performed using flow cytometry as the method of choice. In this study, we also analyzed MRD in t(12;21)(p13;q22) cases with quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for the fusion transcript ETV6-RUNX1 in parallel with routine MRD analysis with flow cytometry, to determine if qRT-PCR of the ETV6-RUNX1 fusion transcript would be a reliable alternative to FACS. Bone marrow samples were collected at diagnosis and at day 15, 29 and 79 during treatment from 31 children treated according to the NOPHO ALL-2000 (n = 3) and NOPHO ALL-2008 (n = 28) protocols in Gothenburg, Sweden, between 2006 and 2013. Samples were analyzed in parallel with qRT-PCR for ETV6-RUNX1 fusion transcript and with FACS. For qRT-PCR, mRNA was isolated, cDNA synthesized, and qRT-PCR performed with GUSB as reference gene. MRD-qRT-PCR was defined as the ETV6-RUNX1/GUSB ratio at the follow-up time point (day 15/29/79) divided with the ETV6-RUNX1/GUSB ratio at diagnosis (%). MRD analysis with FACS was performed, after lysis of erythrocytes, using antibodies against CD10, CD19, CD20, CD22, CD34, CD38, CD45, CD58, CD66c, CD123, and terminal deoxynucleotidyl transferase, and when applicable also CD13 and CD33. Results of MRD-FACS were expressed as % of all cells. In total, 83 samples were analyzed with both methods in parallel; 31 from day 15 in treatment, 28 from day 29, and 24 from day 79. Overall, MRD-qRT-PCR showed good correlation with MRD-FACS. In total, 31 samples were positive with qRT-PCR and 24 with FACS, with concordant results (positive with both methods or negative with both methods) in 89% of samples, when the limit of decision (positive/negative MRD) was set to 0.1%. The concordance was especially high at the treatment stratifying time points, i.e. day 29 and 79; 89% and 100%, respectively. No samples at these time points were positive with FACS but negative with qRT-PCR. During the follow-up period (6-81 months), one patient relapsed (with negative MRD with both methods at stratifying time points), and two succumbed from therapy-related causes. Our results show that there is a significant relationship between the results of MRD analysis using FACS and MRD analysis using qRT-PCR of ETV6-RUNX1 fusion transcript. The high concordance between the methods indicates that negative MRD using qRT-PCR is as reliable as negative MRD using FACS, and that qRT-PCR could therefore be an alternative to FACS in cases where FACS is not achievable. In comparison to quantitative PCR of TCR/Ig gene rearrangements, which is the current backup MRD method for cases with pre-B ALL in NOPHO ALL-2008, qRT-PCR of ETV6-RUNX1 is much less time and labor consuming, making it appealing in a clinical laboratory setting. Disclosures No relevant conflicts of interest to declare.

Identification of a Rare e8a2 BCR-ABL Fusion Gene in Three Novel Chronic Myeloid Leukemia Patients Treated with Imatinib.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4830-4830
Author(s):  
Jean-Michel Cayuela ◽  
Philippe Rousselot ◽  
Franck Nicolini ◽  
Daniel Espinouse ◽  
Christophe Ollagnier ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Fusion Gene ◽  
Chronic Phase ◽  
Fusion Transcript ◽  
Molecular Response ◽  
Major Molecular Response ◽  
Minor Response ◽  
Worse Prognosis

Abstract Most patients with chronic myeloid leukemia (CML) express the BCR-ABL transcript with the b2a2 (e13a2) or b3a2 (e14a2) junctions corresponding to the major BCR gene breakpoint cluster region (M-BCR). We and others have reported that a small proportion of CML patients (1–2%), which have breakpoints that fall outside of the M-BCR, giving rise to shortened BCR-ABL transcripts (m-BCR, e6a2, b2a3, b3a3) or longer BCR-ABL transcripts (μ-BCR). The clinical and hematologic features of 8 additional patients with e8a2 BCR-ABL fusions transcripts have been recently reviewed (Demehri et al, Leukemia 2005) and, according to the authors, could be associated with thrombocytosis and a worse prognosis than common M-BCR transcripts. Here, we report three additional CML patients with an e8a2 BCR-ABL fusion transcript treated with imatinib and who achieved hematologic, cytogenetic remission. Molecular studies allowed us to quantify this rare BCR-ABL fusion mRNA. All the patients showed a major molecular response with a reduction of at least 3 logs compared to initial samples at a median follow-up of 34 months (range 30–39). None of the cases (patients #1, 2 and 3) described here showed thrombocytosis at diagnosis. The diagnosis of chronic phase CML was based on typical peripheral blood findings and cytogenetics. In all cases, standard karyotyping demonstrated a t(9;22)(q34;q11), but further molecular analysis revealed an atypical e8a2 BCR-ABL fusion gene. In case #1, FISH using the LSI-bcr/abl ES probe (Vysis) showed a typical M-BCR picture which was different with the case previously described. Multiplex RT-PCR for BCR-ABL and sequencing showed a fusion between BCR exon e8 and ABL exon a2, with a 55 base pair (bp) insert, which perfectly matched an inverted sequence from ABL intron Ib. Most of the patients with an e8a2 BCR-ABL fusion transcript previously described seem to be associated with a worse prognosis because none of them treated with interferon achieved even a minor response. Here, all the patients are alive, achieved complete cytogenetic and major molecular responses with a prolonged follow up, confirming thus the efficacy of imatinib mesylate in patients with rare BCR-ABL transcripts. Of note, in cases #2 and #3, the major molecular response was obtained after increasing the dosage of imatinib (400 to 600 mg/day), suggesting that those patients may require higher doses of imatinib to achieve proper molecular response. The aggressive clinical course of these leukemias could be shrouded by appropriate targeted therapy. A longer follow-up and the analysis of a large cohort of patients with e8a2 BCR-ABL fusions are necessary to analyse the clinical outcome of these patients. The study of these unusual transcripts is essential to gain more insights of their molecular pathological function and a more comprehensive survey of the different functions of the BCR-ABL chimeric protein.

Impact of Minimal Residual Disease (MRD) on Prognosis in Children with Acute Lymphoblastic Leukemia (ALL) According to WBC Count, Age and TEL/AML1 Status at Diagnosis. Results of the AIEOP-BFM ALL 2000 Study.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 544-544 ◽  
Author(s):  
Valentino Conter ◽  
André Schrauder ◽  
Helmut Gadner ◽  
Maria Grazia Valsecchi ◽  
Martin Zimmermann ◽  
...  
Keyword(s):  
Minimal Residual Disease ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Patient Specific ◽  
Specific Gene ◽  
Childhood All ◽  
Historical Factors ◽  
Wbc Count ◽  
Minimal Residual

Abstract Minimal residual disease (MRD), the most sensitive method to evaluate treatment response, has been adopted to stratify patients in study AIEOP-BFM ALL 2000. To assess whether PCR-MRD levels discriminate outcome in patients classified by WBC count, age at diagnosis, NCI criteria (Standard Risk, SR: WBC < 50,000/cmm and age 1–9 years; High Risk, HR: all others) and TEL/AML1 status. Between 07–2000 and 07–2006, 4,730 Ph-negative patients were enrolled in AIEOP-BFM ALL 2000 study. They were treated with BFM Induction (protocol IA) consolidation (protocol IB), extra-compartment/intensified consolidation (HD-MTX in non-HR patients, blocks in HR patients), reinduction therapy (one or more Protocols II or III), followed by maintainance. BM samples obtained at weeks 5 (Time Point 1, TP1) and 12 (TP2) of induction/consolidation therapy were used for PCR-based MRD analysis of patient specific gene targets. At least 2 sensitive markers (≥ 1 x 10−4) could be determined in 3,707 (78.4%) patients. SR was defined by MRD− at both TP1 and TP2; HR by MRD ≥1x10−3 at TP2; Intermediate Risk (IR): all others. Median follow-up was 3 years; 5-year percent EFS (SE) estimates are given.Patients at MRD-SR, IR or HR had, respectively, an EFS of 93.0 (1.0), 80.5 (1.5) and 43.4 (6.0) in patients with WBC <50,000/cmm vs 90.4 (2.6), 72.4 (3.0) and 47.0 (5.1) in patients with WBC ≥50,000/cmm. Patients at MRD SR, IR or HR had, respectively, EFS of 93.6 (1.0), 80.3 (1.5) and 44.1 (5.4) if aged 1–9 years vs 87.2 (3.4), 73.9 (3.0) and 49.3 (5.2) if aged ≥10 years. Patients at SR by NCI criteria [N= 2,355, EFS of 85.3 (1.0)] were stratified by PCR-MRD as SR (N=1046; 44.4%), IR (N=1198; 50.9%), or HR (N=111; 4.7%). EFS in these subgroups was 93.9 (1.0), 81.3 (1.6) and 43.9 (7.2), respectively (p<0.001). In patients at HR by NCI criteria [N=1,352, EFS of 75.6 (1.6)], 403 (29.8%), 774 (57.3%) and 175 (12.9%) respectively were at SR IR and HR by MRD. EFS was 89.4 (2.2) in MRD SR, 74.7 (2.3) in MRD IR and 47.9 (4.2) in MRD HR patients (p<0.001). Of 3,707 study patients, 3,410 were investigated for TEL/AML1 status: 771 (22.6%) were positive and 2,639 were negative. TEL/AML1+ patients were at SR (N=444; 57.6%) or IR (N=317; 41.1%) or HR (N=10; 1.3%) by PCR-MRD; EFS in this subgroup was 94.4% (1.5), 80% (3.7) and 60% (18.4), respectively (p<0.001). TEL/AML1− patients at SR (N=887; 33.6%) or IR (N=1497; 56.7%) or HR (N=255; 9.7%) had an EFS of 91.6% (1.3), 78.5% (1.4) and 45.7% (4.5), respectively (p<0.001). PCR-MRD in patients treated with BFM-oriented therapy overcomes the prognostic value of “historical” factors such as WBC count, age, NCI criteria or TEL/AML1 status, as it markedly discriminates prognosis within each subgroup defined by these variables. Study design for contemporary risk-directed therapy of childhood ALL should incorporate a technique for MRD determination.

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