Expression of DNA repair enzyme hMTH1 mRNA and protein in hepatocellular carcinoma

To study the expression of DNA repair enzyme hMTH1 mRNA and protein in hepatocellular carcinoma (HCC) tissues, tissues adjacent to the cancers, normal liver cells and hepatoma cell lines, and to investigate their function in the progress of HCC, semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) was employed to examine the expression of hMTH1 mRNA in matched HCC tissues (HT)/surrounding tissues (HST) of HCC, normal liver cell L02 and hepatoma cell lines SMMC7721, HepG2. hMTH1 protein was detected in corresponding HT as well as their HST by immunohistochemistry. Our results showed that the expression level of hMTH1 mRNA in HT was higher than that in HST (t = 2.424, P < 0.05). The expression level of hMTH1 mRNA in two hepatoma cell lines was higher than that in normal liver cell line (F = 6.810, P < 0.01). The expression of hMTH1 mRNA in SMMC7721 was similar to that in HepG2. hMTH1 protein was 88.2% (15 of 17) positive in HT and 82.4% (14 of 17) in HST. The protein level of hMTH1 in HT was correspondingly higher than in their HST (t = 2.18, P < 0.05). It is concluded that hMTH1 mRNA and protein were over-expressed in HCC and hepatoma cell lines. It may be one of the key events during the carcinogenesis, progression of HCC and may promote the malignant growth. These results suggest that hMTH1 plays a role in HCC and may be a candidate marker for the diagnosis of HCC.