Heterogeneity Of CXCR4 Expression In Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4652-4652
Author(s):  
Tomasz Szczepanski ◽  
Urszula Malek ◽  
Lukasz Sedek ◽  
Alicja Sonsala ◽  
Joanna Zawitkowska ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Lymphoblastic Leukemia ◽  
Residual Disease ◽  
Risk Group ◽  
Lymphoblastic Leukemia ◽  
Cxcr4 Expression ◽  
Study Group ◽  
Cell Precursor ◽  
Minimal Residual

Background CXCR4 (CD184) is a receptor specific to the Stromal Derived Factor 1 (SDF-1), a ligand also known as CXCL12. The ligand-receptor interaction has a pleiotropic effect on hematopoietic cell proliferation, migration and activation through several signaling pathways. CXCR4 expression on neoplastic cells might be responsible for their dissemination to particular organs with cells expressing CXCL12 (e.g. lymph nodes, bones, and within bone marrow). In B-cell precursor acute lymphoblastic leukemia (BCP-ALL), expression of CXCR4 was associated with higher capacity of leukemic blasts to seed into bone marrow niches. Aim of the study The study aimed at thorough analysis of CXCR4 expression on BCP-ALL blasts and correlation of CXCR4 expression with the expression of other antigens such as CD66c, CD34, CD10, CD38, CD20 and CD45 as well as with the levels of minimal residual disease on day 15. Patients and methods The study group consisted of 198 consecutive children aged 0-18 years (median 4.4 years) treated for BCP-ALL in the centers of the Polish Pediatric Leukemia/Lymphoma Study Group. Bone marrow samples obtained at initial diagnosis were stained with monoclonal antibodies (CD58, CD66c, CD34, CD19, CD10, CD38, CD20, CD45, CXCR4) in two 8-color tubes and analyzed with multiparameter flow cytometry (BD FACS Canto II, Becton Dickinson, San Jose, CA, USA) according to the EuroFlow standard protocols. The expression of particular antigens on BCP-ALL blasts was defined by median fluorescence. In 177 patients the samples from day 15 were available and analyzed for the presence of minimal residual disease (MRD) with multicolor flow cytometry. Infinicyt software (Cytognos, Salamanca, Spain) was used for more detailed analyses of the flow cytometric data. Results The expression of CXCR4 in BCP-ALL was highly variable with median fluorescence ranging from 252 to 24 388 (median 4011). There was no obvious correlation of CXCR4 expression with immunophenotype and with the expression of other analyzed markers (CD66, CD34, CD10, CD38 i CD45). The only borderline significant correlation found was between CXCR4 and CD20 expression. On day 15, 70 children (39%) demonstrated MRD levels below 0.1%, which is consistent with MRD-based low-risk group. Among these patients, 41 children had undetectable MRD already at this time point. In contrary, MRD levels > 10% were recorded in 21 patients (12%), who were stratified to high-risk group, accordingly. Maximal MRD levels recorded at day 15 were 85.6%. In remaining 86 children (49%), MRD levels at day 15 were in-between 0.1% and 10%, which reflects intermediate response to the treatment. There was no correlation between CXCR4 expression and MRD levels at day 15. Conclusion CXCR4 expression on BCP-ALL blasts is highly heterogeneous and is not associated with particular leukemia immunophenotype. Further analyses should characterize clinical features of leukemia and treatment response with regard to CXCR4 expression. The study was supported by Polish National Center of Science grant N N407 687040. Disclosures: No relevant conflicts of interest to declare.

Heterogeneity Of CXCR4 Expression In Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4952-4952
Author(s):  
Tomasz Szczepanski ◽  
Urszula Malek ◽  
Lukasz Sedek ◽  
Alicja Sonsala ◽  
Joanna Zawitkowska ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Lymphoblastic Leukemia ◽  
Residual Disease ◽  
Risk Group ◽  
Lymphoblastic Leukemia ◽  
Cxcr4 Expression ◽  
Study Group ◽  
Cell Precursor ◽  
Minimal Residual

Abstract Background CXCR4 (CD184) is a receptor specific to the Stromal Derived Factor 1 (SDF-1), a ligand also known as CXCL12. The ligand-receptor interaction has a pleiotropic effect on hematopoietic cell proliferation, migration and activation through several signaling pathways. CXCR4 expression on neoplastic cells might be responsible for their dissemination to particular organs with cells expressing CXCL12 (e.g. lymph nodes, bones, and within bone marrow). In B-cell precursor acute lymphoblastic leukemia (BCP-ALL), expression of CXCR4 was associated with higher capacity of leukemic blasts to seed into bone marrow niches. Aim of the study The study aimed at thorough analysis of CXCR4 expression on BCP-ALL blasts and correlation of CXCR4 expression with the expression of other antigens such as CD66c, CD34, CD10, CD38, CD20 and CD45 as well as with the levels of minimal residual disease on day 15. Patients and Methods The study group consisted of 198 consecutive children aged 0-18 years (median 4.4 years) treated for BCP-ALL in the centers of the Polish Pediatric Leukemia/Lymphoma Study Group. Bone marrow samples obtained at initial diagnosis were stained with monoclonal antibodies (CD58, CD66c, CD34, CD19, CD10, CD38, CD20, CD45, CXCR4) in two 8-color tubes and analyzed with multiparameter flow cytometry (BD FACSCanto II, Becton Dickinson, San Jose, CA, USA) according to the EuroFlow standard protocols. The expression of particular antigens on BCP-ALL blasts was defined by median fluorescence. In 177 patients the samples from day 15 were available and analyzed for the presence of minimal residual disease (MRD) with multicolor flow cytometry. Infinicyt software (Cytognos, Salamanca, Spain) was used for more detailed analyses of the flow cytometric data. Results The expression of CXCR4 in BCP-ALL was highly variable with median fluorescence ranging from 252 to 24 388 (median 4011). There was no obvious correlation of CXCR4 expression with immunophenotype and with  the expression of other analyzed markers (CD66, CD34, CD10, CD38 i CD45). The only borderline significant correlation found was between CXCR4 and CD20 expression. On day 15, 70 children (39%) demonstrated MRD levels below 0.1%, which is consistent with MRD-based low-risk group. Among these patients, 41 children had undetectable MRD already at this time point. In contrary, MRD levels > 10% were recorded in 21 patients (12%), who were stratified to high-risk group, accordingly. Maximal MRD levels recorded at day 15 were 85.6%. In remaining 86 children (49%), MRD levels at day 15 were in-between 0.1% and 10%, which reflects intermediate response to the treatment. There was no correlation between CXCR4 expression and MRD levels at day 15. Conclusion CXCR4 expression on BCP-ALL blasts is highly heterogeneous and is not associated with particular leukemia immunophenotype. Further analyses should characterize clinical features of leukemia and treatment response with regard to CXCR4 expression. The study was supported by Polish National Center of Science grant N N407 687040. Disclosures: No relevant conflicts of interest to declare.

Role Of Day-15 Peripheral Blood MRD Assessment In Pediatric B-ALL Patients

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1384-1384
Author(s):  
Karthik B.K Bommannan ◽  
Man Updesh Singh Sachdeva ◽  
Parveen Bose ◽  
Deepak Bansal ◽  
Ram Kumar Marwaha ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Lymphoblastic Leukemia ◽  
Minimal Residual Disease ◽  
Peripheral Blood ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Childhood Acute Lymphoblastic Leukemia ◽  
Minimal Residual ◽  
Risk Of Relapse

Abstract Introduction Minimal residual disease (MRD) has emerged as an independent prognostic factor for patients of acute lymphoblastic leukemia (ALL). There is a strong correlation between MRD levels in bone marrow and the risk of relapse in childhood & adult leukemias 1, 2. Bone marrow MRD (BM-MRD) level of ≥ 0.01% is considered as positive and a mid-induction MRD of ≥ 1% is associated with high risk of relapse 3. Recently, the concept of peripheral blood MRD (PB-MRD), as a replacement for BM-MRD, has hit the lime light. In pediatric B-ALL, presence of PB-MRD is associated with a high relapse rate in comparison to cases which are PB-MRD negative 4, 5. This study was aimed to compare the levels of mid-induction (day 15) MRD levels in bone marrow and peripheral blood of pediatric B-ALL patients with a hypothesis that PB-MRD levels correlate with BM-MRD levels, and thus can predict BM-MRD levels for further management of the patient. Methods Forty newly diagnosed CD19+CD10+CD34+/- pediatric B-ALL patients under Vincristine, L-Asparaginase and Dexamethasone, were assessed for MRD levels on their paired day 15 PB & BM samples using six colour flow cytometry. With informed consent, both the samples were collected in EDTA vacutainers and lyse-stain-wash technique was used to prepare a single six colour tube comprising of SYTO 13/ CD34PE/ CD20PerCP/ CD19 PECy7/ CD10APC/ CD45APCH7 for each sample. The processed samples were run on BD FACS Canto II with acquisition of 1 million events or till the tubes were empty. Analysis was done using BD FACS Diva software and MRD of ≥ 0.01% was considered positive. Results Among 40 pairs of day 15 PB and BM samples, 25 (62.5%) were BM-MRD positive. Sixteen pairs (40%) had PB-MRD and BM-MRD co-positivity, 9 pairs (22.5%) had isolated BM-MRD positivity and 15 pairs (37.5%) were MRD negative in both PB and BM samples. In other words, among the 25 BM-MRD positive cases, simultaneous PB-MRD was positive in 16 patients (64%) and none of the samples had isolated PB-MRD positivity. Overall analysis of MRD positive cases showed a direct correlation between PB-MRD and BM-MRD (ρ = +0.684, p < 0.000) and BM-MRD levels were 7 times higher than the PB-MRD. In addition, ROC analysis with PB-MRD of ≥ 0.01% as a cut-off, revealed that, the most likelihood of PB-MRD being positive was when BM-MRD was ≥ 0.31%. Conclusions In contrast to the sparsely available literature, our study shows a significant correlation between PB & BM-MRD levels in day 15 paired samples of B-ALL cases. The MRD levels were 7 times higher in BM as compared to PB and PB-MRD was mostly positive with BM-MRD of ≥0.31%. In other words, day 15 PB-MRD positivity indirectly indicates that there is a minimum BM-MRD of 0.31%. Since literature reports prognostic significance of mid-induction BM-MRD at levels ≥1%, on day 15, an assessment of peripheral blood MRD alone, might yield clinically relevant prognostic information. A paired analysis at different time points might also establish a similar correlation as seen in the present study, eliminating the need of BM-MRD during further follow ups of the patient. This will help in avoiding an invasive procedure and improve patient compliance. References 1. Irving J, Jesson J, Virgo P, Case M, Minto L, Eyre L, et al. Establishment and validation of a standard protocol for the detection of minimal residual disease in B lineage childhood acute lymphoblastic leukemia by flow cytometry in a multi-center setting. haematologica. 2009;94(6):870-4. 2. Coustan-Smith E, Sancho J, Behm FG, Hancock ML, Razzouk BI, Ribeiro RC, et al. Prognostic importance of measuring early clearance of leukemic cells by flow cytometry in childhood acute lymphoblastic leukemia. Blood. 2002;100(1):52-8. 3. Basso G, Veltroni M, Valsecchi MG, Dworzak MN, Ratei R, Silvestri D, et al. Risk of relapse of childhood acute lymphoblastic leukemia is predicted by flow cytometric measurement of residual disease on day 15 bone marrow. Journal of Clinical Oncology. 2009;27(31):5168-74. 4. Elain CS, Sancho J, Michael LH, Bassem. Use of peripheral blood instead of bone marrow to monitor residual disease in children with acute lymphoblastic leukemia. Blood. 2002;100 (7):2399-402. 5. Brisco MJ, Sykes PJ, Hughes E, Dolman G, Neoh SH, Peng LM, et al. Monitoring minimal residual disease in peripheral blood in B lineage acute lymphoblastic leukaemia. British journal of haematology. 1997;99(2):314-9. Disclosures: No relevant conflicts of interest to declare.

Use Of Rearranged Immune Receptor Sequencing To Measure Minimal Residual Disease (MRD) In Bone Marrow, Cerebrospinal Fluid and Testes In Relapsed Childhood Acute Lymphoblastic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4984-4984
Author(s):  
Norman J. Lacayo ◽  
Li Weng ◽  
Charles Gawad ◽  
Malek Faham ◽  
Gary V Dahl
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Cerebrospinal Fluid ◽  
Acute Lymphoblastic Leukemia ◽  
Deep Sequencing ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Employment Equity ◽  
Equity Ownership ◽  
Minimal Residual

Abstract Background Detection of minimal residual disease (MRD) in pediatric acute lymphoblastic leukemia (ALL) is a strong predictor of outcome. In addition, MRD testing prior to stem cell transplant for ALL can inform on the risk of relapse. The ClonoSIGHT test uses deep sequencing of immunoglobulin and T-cell receptors to identify and monitor MRD. In retrospective cohorts, we have previously shown this technology is highly correlated with flow cytometry and PCR-based MRD methods, but has even greater sensitivity than both technologies (Faham et al, Blood 2012; Gawad et al, Blood 2012).  Here we report on four clinical cases where we used the ClonoSIGHT assay to prospectively monitor MRD, in both the medullary and extramedullary compartments, to demonstrate the feasibility of this technology for MRD monitoring of children with relapsed ALL. Methods Universal primer sets were used to amplify rearranged variable (V), diversity (D), and joining (J) gene segments from the immunoglobulin heavy and kappa chain (IGH and IGK), as well as T-cell receptor beta, delta and gamma.  The assay was performed on genomic DNA isolated from cells from the bone marrow, cerebrospinal fluid, or testes.  The test was first done at the time of relapse to identify the malignant clonotype, which was monitored at subsequent time points. The patients were ineligible for clinical trials and concurrently underwent MRD testing using flow cytometry. The sequencing assays were performed to show feasibility of the approach. Results  Patient one was a 14 y/o ALL relapse patient who was not in morphologic remission after standard re-induction therapy. The malignant clonotype was identified on a bone marrow aspirate from relapse; follow-up MRD tests were done using both flow cytometry and deep sequencing five times throughout salvage therapy with 5-aza-2'-deoxycytidine, suberoylanilide hydroxamic acid and high dose cytarabine over 75 days; the last two MRD data points showed 0.6% and 6% by ClonoSIGHT MRD and 0.4% and 1.3% by flow cytometry MRD. Morphologic remission with count recovery was used as the criteria to direct this patient to SCT. Patient two was a 9 y/o with ALL, for whom MRD was used to test for relapsed disease in multiple tissues.  This patient experienced three isolated testicular relapses (M1 marrow and no CNS involvement) at the time of each relapse. The ClonoSIGHT assay was used on tissue from a testicular biopsy to identify the malignant clone(s).  Testing of the bone marrow and cerebrospinal fluid did not detect the malignant clones in those sites. This patient underwent therapeutic orchiectomy and 4-week systemic re-induction resulting in a fourth complete remission and now is under evaluation for consolidation therapy with a SCT. A third patient was an 8 y/o with a combined bone marrow and testicular ALL relapse, who was in morphologic remission in the marrow after re-induction therapy and testicular radiotherapy. Prior to undergoing SCT the patient had negative MRD by flow cytometry but had 0.008% MRD using the ClonoSIGHT MRD assay.  The fourth patient was a 15-yo with ALL relapse at 9 years from first remission, treated with a four-drug re-induction and Berlin-Frankfurt-Münster based consolidation and maintenance therapy.  This patient was MRD negative by both flow cytometry and ClonoSIGHT MRD at end of re-induction as well as end of consolidation and remains in remission. Conclusions We have shown the feasibility of using sequencing-based tests for monitoring MRD in children with relapsed ALL in medullary (bone marrow) and extramedullary compartments (testes and CSF).  Further studies are needed to establish the prognostic value of MRD detected by the ClonoSIGHT assay in both medullary and extramedullary sites that are below the limit of detection of PCR and flow cytometry. These sequencing-based tests may provide a useful tool to develop risk stratification schemas for drug development in relapsed childhood ALL. Disclosures: Weng: Sequenta, Inc.: Employment, Equity Ownership. Faham:Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees.

Value of Day 21 Flow Cytometry Minimal Residual Disease Assessment in Childhood Acute Lymphoblastic Leukemia (ALL) for Early Identification of Good Responders

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5358-5358
Author(s):  
Marion Eveillard ◽  
Nelly Robillard ◽  
Richard Garand ◽  
Fanny Rialland ◽  
Nicolas Blin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Lymphoblastic Leukemia ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Good Prognosis ◽  
Level 3 ◽  
Blast Cells ◽  
Minimal Residual ◽  
Time Point

Abstract The efficacy of induction chemotherapy in childhood acute lymphoblastic leukemia (ALL) is usually evaluated on day 35. However, at this stage, many patients have already begun to recover and present with a regenerative bone marrow (BM) where hematogones may make the identification of residual blast cells problematic both in morphology and in flow cytometry (FCM). In the FRALLE (French Acute Lymphoblastic Leukemia) trials, evaluation is proposed on days 8, 21 and 35. Here we evaluated whether FCM performed on day 21 (D21), when hematogones are still absent, would prove informative. The cohort reported here was constituted of 45 children aged between 1 and 20 years old (median 6) treated for ALL according to the FRALLE recommendations since 2006. There were 81% B-ALL, 17% T-ALL and 2% of mixed phenotype acute leukemia (MPAL, T/My). At diagnosis, the mean percentage of BM blasts was 50%. Classification according to the European Group for Immunophenotyping of Leukemia (EGIL) was 3 B-I, 21 B-II, 11 B-III, 2 B-IV and 1 T-I, 2 T-II and 4 T-III. Extensive immunophenotyping at diagnosis identified a median of 3 leukemia associated immunophenotypes (LAIP, range 1-5), defined as discriminant from hematogones. Corticosensitivity was defined on a complete blood count (CBC) as less than 1 G/L of blast cells on day 8. Chemosensitivity was assessed on a bone marrow aspiration at day 21, both morphologically (< 5% blasts) and in FCM (MRD0). Molecular biology (according to Biomed2) was performed on BM samples collected on days 35 (MRD1) and 70 (MRD2). Follow-up median time was 59 months (3-276). Corticosensitivity was observed for 39/43 patients (one had received corticosteroids for a tonsillitis before being referred and diagnosed with ALL and another one had less than 1 G/L of blasts at diagnosis). Five/44 patients were identified as chemoresistant by morphology on D21 (one aplastic sample). Enough cells were available for minimal residual disease (MRD) by FCM in 43 patients, on bone marrow collected on EDTA. As a mean, 586 328 total nucleated cells were acquired in FCM (range 9 616 - 1 751 000) thereby providing good sensitivity. Multiparameter FCM in 6 to 8 colors was performed on a single tube, customized according to each patient’s LAIP. Five MRD thresholds were defined as follows : level 1, >10-2 detected blasts; level 2, 10-3- <10-2detected blasts; level 3, 10-4- <10-3detected blasts; level 4, 10-5- <10-4 detected blasts or no event detected; level 5, <10-5detected blasts or no event detected. The table below indicates the partition of patients according to these MRD levels on D21. Table 1LevelPatient numbersDetectable MRDAbsence of MRD166028803660415695818 Event-free survival (EFS; Kaplan Meier Log rank test) was statistically significant (p=0.023) when comparing patients with level 4 or 5 MRD to the others. Level 3 patients had an intermediate EFS and OS. In an independent cohort of 79 patients with evaluable FMC MRD on day 21 from a different center, the same good prognosis value of MRD lower than 10-4at that time point was confirmed for EFS (p=0.03). Childhood ALL has become of relatively good prognosis with the progress in therapies. However, it is noteworthy that half the patients had detectable MRD at levels 1, 2 or 3, which probably prompted the clinicians to intensify treatment. However, below level 3, i.e.<10-4, FCM MRD on D21 is of excellent prognosis, even if detectable. In summary, this work demonstrates the feasibility of FCM evaluation on D21, with the advantage of not being complicated by the presence of hematogones. Moreover, interpretation remains delicate in morphology at this time point where BM smears may be very poor. FCM thereby provides precious early information on chemosensitivity with a single patient-adapted antibody combination. Disclosures No relevant conflicts of interest to declare.

scholarly journals Immunophenotypic Modulation of the Blast Cells in Childhood Acute Lymphoblastic Leukemia Minimal Residual Disease Detection

Folia Medica ◽  
2016 ◽  
Vol 58 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Hasan A. Burnusuzov ◽  
Mariya I. Spasova ◽  
Mariana A. Murdjeva ◽  
Angelina A. Stoyanova ◽  
Ivan N. Mumdziev ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Lymphoblastic Leukemia ◽  
Minimal Residual Disease ◽  
Peripheral Blood ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Childhood Acute Lymphoblastic Leukemia ◽  
Leukemic Cells ◽  
Minimal Residual

AbstractEarly clearance of leukemic cells during induction therapy of childhood acute lymphoblastic leukemia (ALL) is a basis for treatment optimization. Currently, the most widely used methods for the detection of minute residual malignant cells in the bone marrow and/or peripheral blood, minimal residual disease (MRD), are PCR and flow cytometry (FCM). Immunophenotypic modulation (IM) is a well known factor that can hamper the accurate FCM analysis.Aim: To report the IM detected by 8-color FCM during the BFM-type remission induction in 24 consecutive MRD-positive samples of children with B-cell precursor ALL and the possible implications for MRD detection.Patients and methods: Between 2010 and 2012 we prospectively followed up the MRD on days 15 and 33 of induction treatment in bone marrow (BM) samples and on day 8 in peripheral blood (PB). The IM was assessed by comparative analyses of the changes in the mean fluorescence intensity of 7 highly relevant antigens expressed by the leukemic cells and normal B-lymphocytes.Results: IM occurred, to different extents, in all analyzed day 15 BM and in most day 33 BM samples. Statistically significant changes in the MFI-levels of four CDs expressed by the leukemic blasts were observed: downmodulation of CD10, CD19 and CD34 and upmodulation of CD20. No changes in the expression of CD38, CD58 and CD45 were noticed.Conclusions: Measuring the MRD by standardized 8-color flow cytometry helps improve the monitoring of the disease, leading to better therapeutic results. However, the IM of the different antigens expressed by the leukemic blasts should be taken into consideration and cautiously analyzed.

scholarly journals Circulating microRNAs as minimal residual disease biomarkers in childhood acute lymphoblastic leukemia

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Andrea Rzepiel ◽  
Nóra Kutszegi ◽  
András Gézsi ◽  
Judit C. Sági ◽  
Bálint Egyed ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Lymphoblastic Leukemia ◽  
Minimal Residual Disease ◽  
De Novo ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Fold Change ◽  
Time Points ◽  
Minimal Residual

Abstract Background Treatment stratification based on bone marrow minimal residual disease (MRD) at set time points has resulted in considerably improved survival in pediatric acute lymphoblastic leukemia (ALL). Treatment response is assessed using bone marrow samples. MicroRNAs (miRs) easily traffic among fluid spaces and are more stable than most other RNA classes. We examined the role of circulating miRs as putative less invasive MRD biomarkers. Methods In an exploratory experiment, expression of 46 preselected miRs was studied in platelet-free blood plasma samples of 15 de novo, 5 relapsed ALL patients and 10 controls by Custom TaqMan Array Advanced MicroRNA Card. Based on their high expression in ALL compared to controls, and on the reduction observed along the induction therapy, four miRs were selected for further analyses: miR-128-3p, -181a-5p, -181b-5p and 222-3p. Their expression was measured by qPCR at 4 time points in 27 de novo ALL patients treated in the ALL IC-BFM 2009 study. Results The expression of all 4 miRs significantly decreased over the first week of therapy (miR-128-3p: log2 fold change − 2.86; adjusted p 3.6 × 10−7; miR-181b-5p: log2 fold change − 1.75; adjusted p 1.48 × 10−2; miR-181a-5p: log2 fold change -1.33; adjusted p 3.12 × 10−2; miR-222-3p: log2 fold change − 1.25; adjusted p 1.66 × 10−2). However, no significant further reduction in miR expression was found after the 8th day of therapy. Measured drop in expression of 2 miRs at day 8 strongly correlated with day 15 bone marrow flow cytometry MRD results (miR-128-3p: Pearson’s r = 0.88, adjusted p = 2.71 × 10−4; miR-222-3p: r = 0.81, adjusted p = 2.99 × 10−3). Conclusion In conclusion, these circulating miRs might act as biomarkers of residual leukemia. MiR-128-3p and miR-222-3p in blood predict day 15 flow cytometry MRD results 7 days earlier. Although, their sensitivity falls behind that of bone marrow flow cytometry MRD at day 15.

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