| Objective:To study the frequency distribution patterns of genotype polymorphism of Cytochrome P450 subfamilyⅢA 5(CYP3A5) in children with acute leukemia and healthy controls,to explore whether CYP3A5 mutation is related to the vulnerability to childhood leukemia;To examine the exprssion of CYP3A5 in different types of childhood acute leukemia and study whether its expression may correlate with the herapeutic efficacy or prognosis.Methods:A case-control study was carried out to compare the distribution of genotype and genetic frequency of CYP3A5-6986 A/G genetic polymorphism between acute leukemia (n=139, contraining 91 acute lymphoblastic leukemia, and 48acute myeloid leukemia patients) and control individuals (n=120) with polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) method. Quantitative real-time RT-PCR was used to examine wt-CYP3A5 and SV1-CYP3A5 mRNA levels in the bone marrow of 34 ALL,32 AML patients and 20 normal controls.Meanwhile the results were analyzed according to gender,FAB subtype,chromosome karyotype respectively.Result:1,Three genotypes(AA,AG and GG) of CYP3A5-6986A/G polymorphism were found; There was sigfificant difference in the distribution of genotype of CYP3A5-6986A/G between the group of the controls and ALL patients, also between the group of the controls and AML patients.2,①Quantitation of CYP3A5 transcription in bone marrow mononuclear cells of acute leukemia patients and the controls.Total mRNA was extracted from 66 bone marrow samples with known CYP3A5 genotype (15CYP3A5*1/1,16CYP35*1/*3and 35CYP3A5*3/*3.) Aberrantly spliced SV1-CYP3A5 mRNA was not detected in the CYP3A5*1/*1 patients but was found in all other patients containing at least one CYP3A5*3 allele .Individual levels of the SV1-CYP3A5 mRNA varied considerably.For each genotype, levels of SV1-CYP3A5 and wt-CYP3A5 mRNA were compared. SV1-CYP3A5 and wt-CYP3A5 mRNA were significantly correlated:r =0.790 for CYP3A5*1/*3 and r =0.847 for CYP3A5*3/*3. 66 de novo AL patients was divided into three groups according to their CYP3A5 genotype. There was significant difference for wt-CYP3A5mRNA mean levels among them(P<0.05). The results were 27.78±13.25,8.4±3.23,0.8±1.73 respectively.②The mean level of wt-CYP3A5 mRNA in de novo patients was 16.15±19.64,There was no difference f between them and the concrols ,P=0.079 .③The expression of wt-CYP3A5mRNA was different in FAB subtypes,especial between M5 and M3;the level in female was high than that of male,but without statistical significance;number of chromesome has no influence on the wt-CYP3A5mRNA expression in acute leukemia patients.The levels of e novo ALL patients with t(1;19),t(9;22)or t(9;22)chromesome translocation were higher than those with normal chromesome karyotype .④51 cases were divided into wt-CYP3A5hi group and wt-CYP3A5lo group. As to ALL patients,the CR rate of wt-CYP3A5lo group, is significantly higher than that in wt-CYP3A5hi group,P=0.034.⑤There were two cases of acute lymphoblastic leukemia,whose expression levels were detected in different periods.Before relapse,the expression level rised.Conclusion:1,The patients with G allele are might be contributed to the susceptibility of acute leukemia.2,The CYP3A5 mRNA can be detected in leukemia cells of acute leukemia patients.3,The CR rate is low in the de novo acute lymphoblastic leukemia patients of wt-CYP3A5hi group. So it plays a role in prognosis for children with acute leukemia,it could affect treatment reaction and prognosis of childhood acute leukemia.4,It also could be used as the molecular marker of childhooh acute leukemia in the detection of MRD. |
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