| Objective: To study the expression and clinical significances of ecotropic viral integration site 1(EVI1) in Chinese patients with acute myeloid leukemia(AML) and acute lymphoblastic leukemia(ALL).Methods: Bone marrow samples were collected from newly diagnosed 263 Chinese patients with AML and 70 with ALL younger than 80 years of age, and 13 healthy volunteers(as normal control) at the First Affiliated Hospital of Soochow University between 2006 and 2011. Total RNA was extracted from the mononuclear cells isolated from bone marrow by Ficoll method, and the relative expression levels of EVI1 m RNA were measured using the real-time fluorescence quantitative RT-PCR(QRT-PCR). Then, we compared the differences between AML, ALL and normal control in the expression levels of EVI1 m RNA. In addition, we analyzed the correlations between EVI1 m RNA expression and clinical features, such as leukemia subtypes, age, sex, cell karyotypes, white blood counts(WBC), blood platelet counts(PLT), bone marrow blasts(%)(Blasts), NRAS mutation, DNMT3 A mutation, FLT3-ITD mutation, human leukocyte differentiation antigen expression, prognosis, etc.Results:1. The expression levels of EVI1 m RNA of AML and ALL patients were higher than normal control(P < 0.01), but no significance was found between AML and ALL. Furthermore, compared with normal control, the expression levels of EVI1 m RNA in AML-M0 and AML-M6 were lower(P < 0.001), but AML-M1, AML-M2 and AML-M5 were higher(P < 0.05). Besides, B-ALL and T-ALL also had higher expression levels of EVI1 m RNA than normal control(P < 0.05).2. 10.3% of the total number of patients with AML and 20% of the total number of patients with ALL were O-EVI1, and the comparison between AML and ALL had significant difference(P = 0.028). Besides, 38.7% of the total number of patients with AML and 52.9% of the total number of patients with ALL were L-EVI1, the comparison between AML and ALL also had significant difference(P = 0.034). 11 patients with O-EVI1 in AML-M3 accounted for 25.0% of the total AML-M3 patients, which was significantly different when compared with other groups(P = 0.001). However, 100% of AML-M0 patients, 64.3% of AML-M4 patients and 93.4% of AML-M6 patients with L-EVI1 also was significantly different when compared with other groups(P < 0.05).3. Karyotypic analysis: we found that patients with abnormal karyotypes had higher expression levels of EVI1 m RNA compared with normal karyotype in AML(P = 0.001), but no significant difference was found in ALL. Compared with normal control, patients with t(8; 21), inv(16) and +8 karyotypes had lower expression levels of EVI1 m RNA(P < 0.05). Interestingly, patients with t(9; 22) karyotypes had lower expression levels of EVI1 m RNA compared with other patients in B-ALL.4. The relationships between EVI1 m RNA expression levels and human leukocyte differentiation antigen expression were found: in AML, expression levels of EVI1 m RNA were negatively correlated with HLA-DR, CD7, CD34 expression(Spearman test, P < 0.05), whereas the expression of CD15 was positive correlation(Pearson test, P < 0.001). In ALL, expression levels of EVI1 m RNA were negatively correlated with CD14 expression(Spearman test, P = 0.012), whereas the expression of CD10 was positive correlation(Spearman test, P = 0.007).5. The relationships between EVI1 m RNA expression and other clinical features were also found: female patients had a higher proportion of patients with O-EVI1 than male patients in AML(P = 0.019). Over 60-years-old patients had lower expression levels compared to normal controls(P < 0.001) in AML. Expression levels of EVI1 m RNA were positively correlated with PLT in AML-M1 and T-ALL patients(Spearman test, P < 0.05), while EVI1 m RNA expression and Blasts(%) were negative correlation in AML-M3 patients(Pearson test, P < 0.001). Besides, patients with L-EVI1 had higher proportion of FLT3-ITD mutations in AML(P = 0.012).6. The clinical impacts of EVI1 m RNA expression on the prognosis of AML and ALL were found: in AML, patients with H-EVI1 had poorer prognosis compared with Non-H-EVI1 by univariate analysis(P = 0.038, HR = 1.648). Furthermore, multivariate Cox regression analysis indicated that H-EVI1 was an independent prognostic risk factors(P = 0.009, HR = 2.019). In addition, we also found that patients with H-EVI1 had significantly poorer prognosis in AML-M3 patients(Long-Rank test, P = 0.003). However, no significant differences were found in ALL.Conclusions: In summary, EVI1 m RNA expression was significantly different between AML and ALL. AML-M1 and AML-M6 had significantly lower expression levels of EVI1 m RNA, but AML-M3 had higher proportion of patients with O-EVI1. While no significant differences were found between B-ALL and T-ALL. Patients with t(8; 21), inv16 and +8 karyotypes had low expression levels of EVI1 m RNA in AML, and patients with t(9; 22) karyotypes had lower expression levels of EVI1 m RNA in ALL. AML patients with L-EVI1 had a higher ratio of FLT3-ITD mutations. Expression levels of EVI1 m RNA were negatively correlated with Blasts(%) in AML-M3, and positively correlated with PLT in AML- M1 and T-ALL patients. Expression levels of EVI1 m RNA were negatively correlated with human leukocyte differentiation antigen HLA-DR, CD7, CD34 expression, and positively correlated with CD15 expression in AML. However, the expression levels of EVI1 m RNA were negatively correlated to CD14 expression and positively correlated with CD10 expression in ALL. H-EVI1 was an independent adverse prognostic factor in AML, and also showed a poor prognosis in AML-M3 patients, but the prognostic significance was not found in ALL. This study found the number of new clinical significances of EVI1 expression in Chinese patients with acute leukemia, which will contribute to understanding the pathological roles of EVI1 in acute leukemia. |
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