Over-Expression of IGF-IR in Malignant Clonal Cells in Bone Marrow of Myelodysplastic Syndromes.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4832-4832
Author(s):  
Qi He ◽  
Xiao Li ◽  
Zheng Zhang ◽  
Qingqiao Zhang ◽  
Feng Xu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Alkaline Phosphatase ◽  
Myelodysplastic Syndromes ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Expression Level ◽  
Over Expression ◽  
Significant Difference ◽  
Clone Cells

Abstract Abstract 4832 To explore the expression level of insulin-like growth factor-1 receptor (IGF-IR) in malignant clone cells of myelodysplastic syndromes (MDS). Method Fluorescence in situ hybridization (FISH) and immunochemistry (APAAP, alkaline phosphatase anti-alkaline phosphatase) were used together to detect the expression of IGF-IR in the bone marrow cells of 26 MDS patients with known abnormal karyotypes. Result The average IGF-IR expression level on the surface of clone cells from the 26 MDS cases was markedly elevated compared to the corresponding level in normal cells (78.2±13.7% vs 14.1±14.0%,P <0.0001). The percentages of malignant clone cells in all 26 MDS cases were significantly correlated with the respective percentages of IGF-IR positive nucleated cells (r = 0.909; P <0.0001). No significant difference in the IGF-IR expression level on the clone cells were observed either between high- and low-risk MDS patients or among MDS patients with different abnormal karyotypes. Conclusion IGF-IR might be taken as a marker of clone cells in MDS because of its propensity to cause malignant proliferation. Disclosures No relevant conflicts of interest to declare.

Study On the Clonal Origin of Dysplastic Cells by Fluorescence in Situ Hybridization in Myelodysplastic Syndromes.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4858-4858
Author(s):  
Jun Zhang ◽  
Yongquan Xue ◽  
Jinlan Pan ◽  
Yafang Wu ◽  
Juan Shen ◽  
...  
Keyword(s):  
Bone Marrow ◽  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Myelodysplastic Syndromes ◽  
Chromosomal Abnormalities ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Banding Technique ◽  
Clonal Origin

Abstract Abstract 4858 Objective To determining the clonal origin of dysplatic cells in Myelodysplastic syndromes (MDS) . Methods Karyotypic analyses of bone marrow cells using R-banding technique were carried out to determine the chromosomal abnormalities. Interphase fluorescence in situ hybridization (FISH) and morphologic analysis of bone marrow aspirates were performed in the same cells to investigate the clonal origin of dysplatic cells in 8 MDS patients. Result All patients had clonal karyotypic abnormalities: simple abnormality in 1 patient, complex abnormalities in 6 patients, coexistent of two unrelated clones in 1 patient. Most of dysplastic cells in 7 of 8 MDS patients derived from neoplasia clone while 1 patient had a reverse result,no matter what cell lineage was involved. Some of non-dysplastic cells of all patients derived from malignant clone; in 7 patients, the proportion of dysplastic cells in malignant clone were significantly higher than that of non- malignant clone. Conclusion Most of dysplastic cells in MDS derived from malignant clones, while the minority of them derived from non-malignant clones. Thus, it is reasonable to expect that in most cases myelodysplasia is present in malignant clone and can be taken as an important diagnostic evidence for MDS. Disclosures No relevant conflicts of interest to declare.

Extensive apoptosis of bone marrow cells as evaluated by the in situ end-labelling (ISEL) technique may be the basis for ineffective haematopoiesis in patients with myelodysplastic syndromes

2009 ◽  
Vol 62 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Agapi Parcharidou ◽  
Azra Raza ◽  
Theofanis Economopoulos ◽  
Efstathios Papageorgiou ◽  
Dimitra Anagnostou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Myelodysplastic Syndromes ◽  
Bone Marrow Cells ◽  
Marrow Cells

Over-Expression of Cancerous Inhibitor of PP2A (CIP2A) in Bone Marrow Cells from Patients with a Group of High-Risk Myelodysplastic Syndromes

2013 ◽  
Vol 20 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Na Li ◽  
Shinya Abe ◽  
Morito Kurata ◽  
Shiho Abe-Suzuki ◽  
Iichiroh Onishi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
High Risk ◽  
Myelodysplastic Syndromes ◽  
Bone Marrow Cells ◽  
Over Expression ◽  
Marrow Cells

Chromosomal alterations and DNA content in rats during ageing

Genome ◽  
1989 ◽  
Vol 32 (3) ◽  
pp. 389-392 ◽  
Author(s):  
Sarmistha Sen ◽  
Geeta Talukder ◽  
Archana Sharma
Keyword(s):  
Bone Marrow ◽  
Dna Content ◽  
Bone Marrow Cells ◽  
Age Groups ◽  
Chromosome Analysis ◽  
Male Rats ◽  
Age Related ◽  
Significant Difference ◽  
Feulgen Cytophotometry

Chromosome analysis of bone marrow cells from 96 sex-matched Rattus norvegicus of 12 different age groups showed a significant increase in hypodiploid cells with ageing. However, in meiotic preparations from gonadal cells of male rats the frequency of hypodiploid or hyperdiploid cells did not change significantly. In situ DNA estimation of bone marrow nuclei, following Feulgen cytophotometry, also did not show any significant difference with gradual age changes.Key words: senescence, DNA content, age-related changes.

JAK2 Inhibition with TG101348 Inhibits Monosomy 7 Myelodysplastic Syndromes (MDS) Bone Marrow Cells In Vitro: a Potential Targeted Therapy for Monosomy 7 MDS

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 973-973 ◽  
Author(s):  
Matthew J. Olnes ◽  
Andrea Poon ◽  
Zachary Tucker ◽  
Neal S. Young ◽  
Elaine M Sloand
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Myelodysplastic Syndromes ◽  
Mononuclear Cells ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Myeloid Cells ◽  
Dependent Manner ◽  
Monosomy 7

Abstract Abstract 973 The myelodysplastic syndromes (MDS) are bone marrow disorders characterized by cytopenias and a variable risk of progression to acute myeloid leukemia (AML). Monosomy 7 is the second most common cytogenetic abnormality in MDS, and the most frequent karyotypic aberration occurring in aplastic anemia patients following immunosuppressive therapy. Monosomy 7 MDS carries a particularly poor prognosis, with patients manifesting severe cytopenias and a high propensity to develop treatment-refractory AML. There are currently no targeted therapies for this disorder. We previously reported that monosomy 7 bone marrow mononuclear cells (BMMNCs) express high levels of a differentiation-defective granulocyte colony stimulating factor (G-CSF) receptor isoform (IV), an alternative splice variant that exhibits constitutive signaling through the JAK-2 and STAT-1 pathway, while levels of STAT-3 and -5 are unchanged (Sloand et al, PNAS, 2006, 103:14483). As a result, the cell's ability to differentiate is limited, while its ability to proliferate remains intact. Here we examine the effects of the highly selective JAK2 inhibitor TG101348 on monosomy 7 aneuploidy in BMMNCs, as well as the activity of this compound on CD34+ stem cells and CD13+ myeloid cells in culture, and on the JAK-2 signaling apparatus. Incubation of BMMNCs with TG101348 for 5 days significantly decreased absolute numbers of monosomy 7 aneuploid cells in a concentration dependent manner versus vehicle- treated controls (0.187 × 106 vs 1.08 × 106, P=0.007), while diploid cell numbers remained stable (0.338 × 106 vs 0.213 × 106, P=0.50). Flow cytometry experiments demonstrated that incubation with increasing concentrations of TG101348 decreased the absolute number of CD34+CD13- stem cells, and increased numbers of more differentiated CD34-CD13+ myeloid cells, with median CD34+/CD13+ ratios of 6.547 and 2.216 for cells treated with vehicle and 100 nM TG101348, respectively. By immunoblot, STAT-1 protein expression in monosomy 7 BMMNCs treated with 1uM TG101348 was decreased relative to vehicle- treated controls, while there was no difference in STAT-3 and STAT-5 levels. Thus TG101348 decreases monosomy 7 MDS blasts in vitro through inhibition of JAK-2/STAT-1 signaling, a finding that warrants further study of this agent in clinical trials for patients with monosomy 7 MDS and AML. Disclosures: No relevant conflicts of interest to declare.

The Expressions of CD114, CD117 and STAT5 in CD34+CD59− and CD34+CD59+ Bone Marrow Cells of the Patients with Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4404-4404
Author(s):  
Rong Fu ◽  
Shaoxue Ding ◽  
Zonghong Shao ◽  
Lijuan Li ◽  
Hui Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Signaling Pathway ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Granulocyte Colony Stimulating Factor ◽  
Clone Cells ◽  
Stimulating Factor ◽  
Normal Controls ◽  
Marrow Cells

Abstract Abstract 4404 Objective: To measure the expressions of granulocyte colony-stimulating factor receptor (G-CSFR, CD114) and stem cell factor receptor (C-KIT, CD117) on the membrane of CD34+CD59− and CD34+CD59+ bone marrow cells of the patients with paroxysmal nocturnal hemoglobinuria(PNH), and the signaling pathway protein STAT5 within the cytoplasm of those cells. Methods: The expressions of CD114 and CD117 on the cell membrane and STAT5 protein within the cytoplasm of bone marrow CD34+CD59+ and CD34+CD59− cells from 26 PNH patients and 14 normal controls were examined by flow cytometry (FCM). Results: The percentage of CD114 positive cells in CD34+CD59− cells of PNH patients was (43.23±19.77)%,which was significantly lower than that in CD34+CD59+ cells of PNH patients (73.72±17.42) (P<0.01) or normal controls (65.91±13.70)% (P<0.01). There was no statistic difference between the two latter (P>0.05). The percentage of CD117 positive cells in CD34+CD59− cells of PNH patients was (49.20±26.80)%,which was significantly lower than that in CD34+CD59+ cells of PNH patients (67.62±17.41) (P<0.01) or normal controls (70.21±12.68)% (P<0.01). There was no statistic difference between the two latter (P>0.05). The STAT5 MFI in CD34+CD59− and CD34+CD59+ cells of PNH patients and CD34+CD59+ cells of normal controls was (270.01±181.26), (205.05±146.16), (227.39±156.65) respectively. There was no statistic difference among the three groups (P>0.05). Conclusions: In PNH, CD114 and CD117 expressed lower on bone marrow PNH clone cells than normal clone cells, but the expressions of signaling pathway protein STAT5 within the cytoplasm was normal. Disclosures: No relevant conflicts of interest to declare.

Research of Gene Expression in Patients with Myelodysplastic Syndromes.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4433-4433
Author(s):  
Bao-An Chen ◽  
Bo Zhang ◽  
Chong Gao ◽  
Guo-Hua Xia ◽  
Ze-ye Shao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Clinical Significance ◽  
Myelodysplastic Syndromes ◽  
Mononuclear Cells ◽  
Conflicts Of Interest ◽  
Bone Marrow Mononuclear Cells ◽  
Rt Pcr ◽  
Normal People ◽  
Significant Difference

Abstract Abstract 4433 Object This study was aimed to investigate the expression of c-FLIPL, c-FLIPS and DLK1 mRNA in Myelodysplastic Syndromes (MDS) patients, as compared with normal people and AML patients, and to find its clinical significance. Methods The expression of c-FLIPL, c-FLIPS and DLK1 mRNA in bone marrow mononuclear cells (BMNNC) of 16 patients with MDS, 8 patients with AML and 3 controls were detected by RT-PCR. Results The expression of DLK1 mRNA was up-regulated in MDS, including RA and RAEB, as compared with controls(P<0.05). There was no significant difference in expression of DLK1 between RA and RAEB(P>0.05). The expression of DLK1 was significant higher in AML patients, compared with controls(P<0.05). There was no significant difference between MDS and AML patients(P>0.05). The expression of c-FLIPL mRNA was higher than that in controls, both in RA and RAEB(P<0.05). There was no significant difference in expression of c-FLIPL between RA and RAEB(P>0.05). In eight AML patients, c-FLIPL gene's expression was up-regulated, as compared with controls(P<0.05). Between AML and MDS patients, there was no significant difference(P>0.05); The expression of c-FLIPS mRNA had no significant difference between MDS patients and controls(P>0.05), but its expression in RAEB was significant higher as compared with RA patients and controls(P<0.05). And in AML patients, the expression of c-FLIPS was higher than that in controls(P<0.05), but there was no significant difference between AML and MDS patients(P>0.05). Conclusion It is concluded that the expressions of DLK1, c-FLIPL and c-FLIPS mRNA in MDS/AML patients are abnormal as compared with normal people, although there are no significant difference have been found between AML and MDS. These genes may play critical roles in escaping malignant clone of MDS from apoptosis and acquiring the ability to divide unlimitedly, they can become important indexes for evaluating of development in MDS. Disclosures: No relevant conflicts of interest to declare.

Pro- and Antiapoptotic Proteins Expression on Bone Marrow and Peripheral Blood CD34+Cells in Acute Leukemia (AL) Patients

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4996-4996
Author(s):  
Elena E. Khodunova ◽  
Elena N Parovichnikova ◽  
Irina V. Galtzeva ◽  
Sergey M. Kulikov ◽  
Valeri G Savchenko
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Conflicts Of Interest ◽  
Expression Level ◽  
Leukemia Cells ◽  
Control Group ◽  
Healthy Donors ◽  
Cd34 Cells ◽  
Significant Difference ◽  
Blast Cells

Abstract Abstract 4996 It was shown that drug resistance, poor-risk cytogenetics and poor prognosis in AL is associated with high level of Bcl-2 expression and low Bax/Bcl-2 ratio (<0,3). Fas-antigen (CD95) as a protein triggering the extrinsic apoptotic pathway is differently expressed on hematopoietic precursors. More immature CD34+/CD38- AML blast cells have lower expression of Fas/Fas-L and lower Fas-induced apoptosis than CD34+/CD38+cells. CD34+/CD38− leukemia precursors also have a reduced sensitivity to daunorubicin in vitro and increased expression of multidrug resistance genes (mrp/lrp). CD34+ leukemia cells have not yet been properly characterized regarding the expression of angiotensin converting enzyme (ACE) which regulatory influence on hematopoiesis is now beeing extensively investigated. ACE expression on blast cells is high, but it's still unknown how CD34+ACE+ leukemia cells behave after chemotherapy. Recent publications indicate that CD34+ACE+ hematopoietic precursors transplanted into NOD/SCID mice contribute 10-fold higher numbers of multilineage blood cells than their CD34+ACE- counterparts. We have studied the dynamics of Bcl-2, Bax, CD95 and ACE expression on CD34+ cells in peripheral blood (PB) and bone marrow (BM) in AL pts during treatment. PB and BM samples were collected before and on +36 day after chemotherapy. The antigens were detected by flow cytometry using monoclonal antibodies. We calculated 10 000 cells in each sample. 19 pts were included in the study: 10 - AML and 9 - ALL. The control group comprised 8 healthy donors. At time of diagnosis there were 40±5,7% of CD34+ cells in BM and 26±4,9% - in PB. There was no significant difference between AML and ALL. CD34+ cells in BM and PB of healthy donors constituted 1,6% and 0,27%, respectively. After induction therapy (+36 day) CD34+ cells decreased in BM to 6,1%±3,3 (p=0,0001), in PB to 3,7%± 2,7 (p=0,0008) in all pts. The data on antigens expression on CD34+ cells of BM and PB are presented in table 1 CD34+/Bcl-2+ CD34+/Bax+ CD34+/CD95+ CD34+/ACE+ BM PB BM PB BM PB BM PB AML pts n=10 0 day 38±11,6* 41±14 24,4±7,9 29,2±7,6* 16,4±8,5 23,2±7,8 21,7±9,5 20,8±8,7* 36 day 13,5±3,4** 23,7±5** 46,2±11,5 50,3±11 19,9±5,5 36,4±10 34±6,6 35±9,2** ALL pts n=9 0 day 36±11 33,7±12 46,2±9,4 37,4±3,7* 3,4±1,1* 7,1±2,5* 41±10,9 33,2±9,7* 36 day 18,4±5,8 26±8,9 38±11,8 40,5±10 26,2±9,1** 40,9±9,2** 34±10 62,8±10** Donors n=8 11,7±1,6 26,1±5,9 22,8±4 67,8±6,7 13,4±3,2 47,7±11,6 28±5,3 68,2±10,2 * − p<0.05 compare with donors ** − p<0.05 compare with day 0 CD34/Bcl-2 expression in BM in AML pts is significantly higher (p=0,04) at the diagnosis comparing with donors. CD34/Bcl-2 expression in PB in AML pts and in BM and PB in ALL pts is higher too, but not significantly. This expression level decreased substantially in BM and PB in AML pts on +36 day comparing with day 0 (p<0,05). We did not found significant changes in ALL pts. CD34/Bax expression in PB is significantly lower (p=0,003) both in AML and ALL pts in comparison with donors. In AML, not in ALL, chemotherapy caused augmentation of Bax expression in CD34+ BM and PB cells on +36 day. BM and PB CD34+ cells in donors had different expression characteristics of Bcl-2 and Bax, demonstrating much higher level of pro- and antiapoptotic markers in PB cells. On the contrast CD34+ leukemia cells in BM and PB had similar characteristics regarding CD34/Bcl-2 and CD34/Bax expression. This fact demonstrates the heterogeneity of donor CD34+cells in BM and PB and points that leukemia CD34+cells in BM and PB are rather similar. CD95 expression on CD34+ BM and PB before treatment is significantly lower (p=0,01, p=0,008) in ALL pts in comparison with donors, and this expression level increased after chemotherapy (p<0,05). CD34/CD95 expression in AML pts is similar with donors, and we didn't find changes after treatment. CD34/ACE coexpression in BM cells of leukemia pts and donors did not differ much at any time of evaluation. But CD34/ACE expression in PB cells of AML and ALL pts was much lower (p<0,05) than in donors and substantially increased on the day 36. So, our data demonstrate that Bcl-2, Bax, CD95 and ACE expression on CD34+ cells in AL pts and donors significantly differs. The chemotherapy provokes critical changes in CD34/CD95 expression in BM and PB in ALL pts, CD34/Bcl-2 expression in AML pts and ÑÂ34/ACE expression in PB in all AL pts. Disclosures: No relevant conflicts of interest to declare.

Putative Monosomy 5 In Myelodysplastic Syndromes (MDS) Is Probably Resulting From Chromothripsis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1559-1559
Author(s):  
Zuzana Zemanova ◽  
Kyra Michalova ◽  
Halka Buryova ◽  
Jana Brezinova ◽  
Libuse Lizcova ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Myelodysplastic Syndromes ◽  
Poor Prognosis ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Genetic Material ◽  
Interstitial Deletion ◽  
Chromosome 5 ◽  
Snp Arrays ◽  
Marrow Cells

Abstract Background Aberrations of chromosome 5 are common cytogenetic findings in bone marrow cells of patients with myelodysplastic syndromes (MDS). The most frequent is the interstitial deletion of the long arm of chromosome 5 [del(5q)] - occurring as sole abnormality or in combination with additional aberrations in ∼30% of primary and up to 50% of secondary MDS. Extent and breakpoints of deleted segment differs among patients. A critical area deleted in all cases (the common deleted region, CDR) has been localized between bands 5q31.1 and 5q32. Loss of the whole chromosome 5 was described in about 3-8% MDS cases. However, in recent studies it has been shown that many suspected monosomies 5 are in fact cryptic translocations or insertions, undetectable by conventional G-banding. The aim of the study was to perform detailed genome wide analyses of bone marrow cells of MDS patients with suspected monosomy 5 detected by conventional G-banding at diagnosis, to verify the loss of genetic material of chromosome 5, to compare the breakpoints and extent of chromosome 5 deletions in individual patients, and to assess real existence and clinical significance of monosomy 5 in MDS. Patients and methods In the period 2002–2012, bone-marrow samples from 870 adults with newly diagnosed MDS were examined and 80 patients (9.2%) with suspected monosomy 5 were identified (50 males, 30 females; median age 67 years). Karyotypes were analyzed by conventional G-banding, FISH with Vysis DNA probes (Abbott, Des Plaines, IL), and mFISH/mBAND (MetaSystems, Altlussheim, Germany). Genomic imbalances were identified with oligonucleotide CGH-SNP arrays (BlueGnome, Cambridge, UK) or with SNP arrays (Illumina, San Diego, CA). Results All 80 patients presented a complex karyotype with confirmed del(5)(q31). The most frequent breakpoints on chromosome 5 involved bands 5q14.3, 5q34, 5q33.3, 5q11.2, and 5q13.2. On 5p, breaks occurred sporadically (recurrent breakpoints at 5p12, 5p14.1, and 5p15.3). The extent of del(5q) ranged from 23.55 Mb to 131.4 Mb (whole arm). The most proximal and most distal breakpoints were located at 5q11.1 and 5q35.3, respectively. The CDR occurred between bands 5q31.1 and 5q32 (15.1 Mb). No patient with pure monosomy 5 was found. In all cases, parts of the deleted chromosome 5 were fragmented and inserted elsewhere in the genome. A commonly retained region conserved in all patients was established at 5p11.1–p14.2 (22.31 Mb). The most recurrent partners of deleted chromosome 5 in cryptic unbalanced rearrangements were chromosomes 17, 3, 7, and 18. Patients with deleted chromosome 5 involved in complex aberrations have an extremely poor prognosis (in the present cohort, a median OS of only two months). Discussion and conclusions Based on these results, we believe that pure monosomy 5, quoted in the literature, in MDS does not actually exist. It seems that the primary interstitial deletion of 5q is likely the cause of increased genomic instability, which may, under certain circumstances, lead to fragmentation and disintegration of the whole chromosome 5 and to the emergence of additional complex rearrangements. Mechanism responsible for fragmentation of deleted chromosome 5 remains unclear. One of possible explanations might be the phenomenon called chromothripsis, whereby one or more chromosomes or chromosomal regions shatter into pieces in a single catastrophic event. Some of these pieces are then stitched haphazardly together by DNA repair machinery, whereas some of them are lost. This process is resulting in severe genomic damage and fast disease progression. MDS patients with deleted chromosome 5 involved in complex rearrangements should be considered as a unique entity with extremely poor prognosis. Supported by grants RVO-VFN64165/2012, GACR P302/12G157/1, PRVOUK-P27/LF1/1 and MHCR 00023736. Disclosures: No relevant conflicts of interest to declare.

Reduced PLCG1 expression Is Associated with Inferior Survival in Myelodysplastic Syndromes

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1700-1700
Author(s):  
Masayuki Shiseki ◽  
Mayuko Ishii ◽  
Mari Ohwashi ◽  
Kentaro Yoshinaga ◽  
Naoki Mori ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Phospholipase C ◽  
Myelodysplastic Syndromes ◽  
Mononuclear Cells ◽  
Conflicts Of Interest ◽  
Expression Patterns ◽  
Expression Level ◽  
Rt Pcr ◽  
Control Subjects ◽  
Chromosome 20

Abstract The PLCG1 gene encodes phospholipase C g isoform, which is involved in diverse physiological and pathological cellular processes through catalyzing the hydrolysis of phosphatidylinositol 4,5-bisphosphate to produce the second messenger molecules inositol 1,4,5-trisphosphate and diacylglycerole. Until now, roles of phospholipase C g 1 in hematopoiesis have been shown in animal models. Plcg1 deficient mouse lacks erythropoiesis and die in early embryonic stage. In zebrafish model, it was demonstrated that phospholipase C g 1 is required in granulocyte maturation. Physiological and/or pathological role of phospholipase C g 1 in human hematopoiesis has not been elucidated. In human, the PLCG1 gene is located on long arm of chromosome 20. Deletion of long arm of chromosome 20 (del(20q)) is commonly observed in myelodysplastic syndromes (MDS). Previously, we determined the common deleted region (CDR) of del(20q) in MDS, and the PLCG1 gene is located within the CDR. Reduced expression of genes located in the CDR due to haploinsufficiency may play role in molecular pathogenesis of MDS. Therefore, we analyzed PLCG1 expression in bone marrow mononuclear cells in MDS patients with or without del(20q), and investigated its clinical significance in the present study. Mononuclear cells separated from bone marrow samples taken at the time of diagnosis with written informed consent from patients were used. To analyze PLCG1 expression, quantitative RT-PCR was performed. Total RNA was extracted from mononuclear cells and subjected to cDNA synthesis. Real-time RT-PCR was carried out using cDNA as template by the TaqMan probe method (Applied Biosystems) with co-amplification of the endogenous control gene, human GAPDH (Applied Biosystems) were performed. The human PLCG1 primer-probe set was from Applied Biosystems. A total of 109 MDS patients, 65 males and 44 females with median age of 69 years (range: 22-91 years), with (n=20) or without (n=89) del(20q), were included in the present study. They were classified as RCUD (n=11), RCMD (n=55), RARS (n=11), RAEB-1 (n=16), and RAEB-2 (n=16) according to WHO classification. They were categorized in four IPSS risk groups, low risk (n=21), intermediate-1 risk (n=52), intermediate-2 risk (n=20), and high risk (n=6). Relative PLCG1 expression level was significantly reduced in MDS patients with del(20q) compared to control subjects (n=20) (P=0.011). Median values of relative PLCG1 expression level in MDS patients with del(20q) and control subjects were 0.94 and 1.96. In addition, relative expression level of PLCG1 in whole MDS cohort significantly lower than that in control subjects (P=0.046). Expression patterns of PLCG1 among, were not different. Median values of relative PLCG1 expression level in five WHO-subtypes, RCUD, RCMD, RARS, RAEB-1, and RAEB-2 were 1.50, 1.55, 1.29, 1.13, and 1.12, respectively, but no statistically difference was observed. WHO-subtypes with high blast counts (RAEB-1 and RAEB-2) showed trend in association with reduced PLCG1 expression compared with those with low blast counts (RCUD, RCMD, and RARS) (median value: 1.01 vs. 1.54, P =0.11). To investigate prognostic implication of PLCG1 expression in MDS, we analyzed impact of PLCG1 expression on overall survival (OS). Based on PLCG1 expression level, 109 patients were divided into four groups, high (Q1), intermediate (Q2, Q3), and low (Q4) quartiles. Kaplan-Meier analysis demonstrated that the lowest quartile (Q4) showed significantly worse survival compared with remaining quartiles (Q1-Q3) (P =0.0015). The estimated 5-year OS rates in Q1-3 group and Q4 group were 63.2% and 29.7%, respectively. Percentage of patients with WHO-subtypes with high blast count (RAEB-1 and RAEB-2) was significantly higher in Q4 than other quartiles (46.9% vs 22.1%, P =0.019 by Fisher's exact test). The present study demonstrated that reduced PLCG1 expression is associated with inferior clinical outcome, indicating that PLCG1 expression could be a useful prognostic marker in MDS. Association between reduced PLCG1 expression and WHO-subtypes with high blasts counts, suggesting that PLCG1 dysfunction play a role in disease progression. Disclosures No relevant conflicts of interest to declare.

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