Study On PTEN Expression And Mechanism In Acute Leukemia Patients

PARTⅠA Comparison of PTEN Expression Difference on Both Normal Person and Acute Leukemia Patients by Quantitative Flow Cytometry AnalysisObjective To study and comparison of a novel tumor suppressor gene PTEN expression difference on bone marrow cells from both healthy person and acute leukemia patients Methods Bone marrow cell samples were Collected form both 5 normal donors and 36 primary acute leukemia patients, Used Kolmogorov– Smirnov (KS) statistical test to characterize the expression of PTEN in quantitative flow cytometry analysis.Results Lymphocytes, granulocytes and monocytes of five normal bone marrow samples showed comparable levels of PTEN expression, with average D-values of 0.93±0.05, 0.97±0.02, and 0.95±0.03, respectively. By the test of Bone marrow blast cell simples from 36 primary acute leukemia patients, PTEN expression could be detected In the 26 patients with de novo AML (1 M0, 2 M1, 11 M2, 3 M3, 6 M4, 2 M5 and 1 M6) simples tested. Except 1 M4 and 2 M5 patents samples showed approximate PTEN expression level compared with Normal samples, PTEN expression level of other Patient samples significantly lowers than that in normal cell populations. Whereas, particularly PTEN expression difference was detected in samples tested. 8 B-ALL patient samples showed spectacularly low down PTEN expression level with D-values of 0.51±0.05. compared with normal samples. 2 T-ALL patients samples with D-values of 0.74±0 02.Conclusion 1. All AML patients showed perceptible PTEN expression whereas particularly low level than normal samples, differences observed in samples respectively. This observation needs to be validated in more patients, and its implications should be further investigated whether PTEN expression level correlated with leukemia FAB subtype.2. absent/low PTEN expression is a frequent event in B-ALL.PARTⅡThe Investigation of PTEN Expression and Its Promoter Methylation in B-ALL PatientsObjective To study the expression of tumor suppressor PTEN in peripheral blood mononuclear cells of B-ALL patients and involvement of promoter methylation in the loss of PTEN expression in these patients.Methods Kolmogorov– Smirnov (KS) statistical test was used to characterize the expression of PTEN in peripheral blood mononuclear cells from both healthy donors and B-ALL patients in quantitative flow cytometry analysis. PTEN Promoter Methylation status of genomic DNA extracted from the peripheral blood mononuclear cells was determinded by MSP analysis.The peripheral blood mononuclear cells were treated with 5-Aza-2'deoxycytidine for 4 days to study its effect on restoring PTEN expression in B-ALL peripheral blood mononuclear cells.Resuits Compared with the high level PTEN expression in healthy donors(D value 0.941±0.017), PTEN expression could barely be detected in 22(91.6%) B-ALL patients ( D value 0.546±0.115). PTEN Promoter Methylation was detected in 5 B-ALL patients(22.7%)but not in any healthy donor. Moreover, 5-Aza-2'deoxycytidine treatment could restore the PTEN epxression in these patients.Conclusion 1.Low/absent expression of PTEN is a frequent event in B-ALL patients2.promoter Methylation should contribute to the loss of PTEN epression in some of B-ALL patients. PartⅢThe Investigation of Early Cytogenetic Response to Imatinib in Two Patients with CML at Accelerated Phase and Carrying the e19a2 BCR-ABL TranscriptObjective To study implications of e19a2 and CML clinic prognosis, and Imatinib's therapeutic effect on CML patients with e19a2 transcriptsMethod 2 accelerated phase CML patients had been treated by STI571 and tested with e19a2 expression. Periodic Bone Marrow Cytogenetic Analysis, Nested Reverse Transcription Polymerase Chain Reaction Analysis and FISH Analysis also included. Results e19a2 expression detected in 2 patient samples at first begin. No Ph chromosome detected in sample of No.1 Patient by cytogenetic analysis after 9 months STI571 treatment (600mg/Day), only very small quantity of e19a2 fused gene was detected in sample. The other patient was treated by STI571 for 6 months (600mg/Day), no Ph chromosome and +der(22)t(9;22) detected by cytogenetic analysis, +der(22)t(9;22) was detected in only 5% Interphase nuclei.Conclusion 1.the presence of e19a2 transcript might be associated with a unfavorable prognosis in CML.2.imatinib treatment could be also valuable for CML patients with e19a2 rearrangements, even in accelerated phase.