[Amplification of RIT1 in hepatocellular carcinoma and its clinical significance].

ABSTRACT

BACKGROUND & OBJECTIVE: Previous study has demonstrated that high frequent gain of 1q was detected in hepatocellular carcinoma (HCC), 1q21-22 was identified as the minimum overlapping amplified region and might contain the candidate oncogenes involved in HCC. RIT1 gene is located in 1q21.3 region and is a member of Ras subfamily. RIT1 protein is similar to Ras protein in molecular structure and functions. It was speculated that RIT1 gene might be a candidate oncogene in HCC. So, the amplification of RIT1 gene was examined in HCC and was linked with the clinical indicators in this study to explore the possible functions of RIT1 gene in HCC development and progression. METHODS: The fluorescence quantitative polymerase chain reaction(FQ-PCR) method was established successfully. The number of RIT1 gene DNA copies was examined in the tumor tissues and its paratumor tissues from 43 patients with HCC by PE ABI 7000 Sequence Detector. The ratio of the number of RIT1 gene DNA copies between the tumor tissue and its paratumor tissue represented the extent of amplification of RIT1 gene DNA. RESULTS: RIT1 gene DNA was amplified in 11 cases (25.6%)among 43 patients. The mean survival time (15 months) of the RIT1 gene-amplification group is significantly shorter than that (34 months) of the non-amplification group (P = 0.0009); furthermore, the pathological grade and the extent of liver cirrhosis were significantly different between the RIT1 gene-amplification group and the non-amplification group (P< 0.01). CONCLUSION: The amplification of RIT1 gene might be one of the activation ways in HCC and might play an important role in HCC development and progression.