RAD51 and XRCC3 polymorphisms: impact on the risk and treatment outcomes of de novo inv(16) or t(16;16)/CBFβ-MYH11(+) acute myeloid leukemia.

DNA double-strand break repair via homologous recombination (HR) is essential in maintaining genetic integrity, and may modulate susceptibility to the development of acute myeloid leukemia (AML) and influence outcomes of AML. This study was designed to evaluate the effects of polymorphisms in HR repair genes RAD51 and XRCC3 on the risk and treatment outcomes of inv(16)/t(16;16)/CBFβ-MYH11(+) AML. The distribution of polymorphisms in RAD51-G135C and XRCC3-Thr241Met were studied by PCR-RFLP analysis in 625 cases of de novo AML, including 105 cases with inv(16)/t(16;16)/CBFβ-MYH11, 806 family controls and 704 volunteer controls. It was found that the XRCC3-241Met variant significantly increased the risk of the development of the AML with inv(16)/t(16;16) as compared with both the volunteer control (OR=7.22; 95% CI, 4.37-11.91) and the family control (OR=7.99; 95% CI, 5.03-12.69). A retrospective study conducted in 103 inv(16)/t(16;16) AML patients. In multivariate analysis for the potential prognostic factors, the XRCC3-241Met variant significantly reduced disease-free survival (DFS) in complete remission (CR) achieved patients (HR=2.34, 95% CI, 1.32-4.16). These data indicate that the XRCC3-241Met variant may not be only a susceptibility factor to the AML with inv(16)/t(16;16), but also an independent poor-prognostic factor for this AML subtype.