OBJECTIVETo explore the mutation and amplification of RIT1 gene and their correlation with carcinogenesis of hepatocellular carcinoma (HCC).

METHODSThe polymerase chain reactioindirect sequencing method was used for detecting the mutations in the sequence of all 6 exons in the RIT1 gene of 50 HCC tissues and paratumor tissues. And the amplification of RIT1 gene was examined by fluorescence quantitative polymerase chain reaction method.

RESULTSA nucleotide 241 G --> C substitution in exon 5 of RIT1 gene was detected in one patient's HCC tissue, but not in paratumor tissue; this 241 G --> C substitution leads to Glu81Gln amino acid alteration in the conservative domain binding GTP. A nucleotide G --> C substitution in 5'-UTR (-21 bp from initial codon) was detected in all of the 50 HCC tissues and paratumor tissues, and 2- to 297-fold amplification of RIT1 gene was detected in 11 of 43 qualified cases, the amplification frequency being 25.6%.

CONCLUSIONGene amplification is one of the main activating ways of RIT1 gene in HCC, and its amplification might be correlated with HCC carcinogenesis, while point mutation might be not.