Study on mismatch repair genes of chronic myeloid leukemia

Objective: To investigate the expression and regulation mechanism of mismatch repair (MMR) genes in chronic myeloid leukemia (CML).

Methods: Expression of MMR genes hMSH2, hMSH3, hMSH6, hMLH1 and hPMS2 mRNAs in 62 CML patients and K562 cell line were detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Expression of bcr-abl mRNA and MMR genes mRNA were detected by RT-PCR in 26 CML patients with allogeneic peripheral blood stem cell transplantation (allo-PBSCT) and 4 CML patients on imatinib treatment. Expression of bcr-abl mRNA was detected by RT-PCR and tyrosine phosphorylation of BCR-ABL fusion protein by Western blot.

Results: Expression of hMSH2, hMSH3 and hMLH1 mRNA was significantly lower in CML and K562 cells than in normal control (P < 0.05). In 26 CML with allo-PBSCT and 4 CML patients on imatinib treatment, expressions of hMSH2, hMSH3 and hMLH1 mRNA was enhanced while expression of bcr-abl mRNA decreased. In CML MNC after imatinib treatment and in K562 cells, expression of hMSH2, hMSH3 and hMLH1 mRNA was enhanced while tyrosine phosphorylation of BCR-ABL fusion protein decreased.

Conclusions: Expressions of hMSH2, hMSH3 and hMLH1 mRNA were down-regulated by bcr-abl fusion gene.