[WAF1/CIP1 gene expression in human hepatocellular carcinoma and its relationship with p53 mutation]

To study the WAF1 gene expression in human hepatocellular carcinoma(HCC) and its relationship with p53 mutation.

Using semiquantitative reverse transcriptase-polymerase chain reaction(RT-PCR) and immunohistochemistry, the expression of WAF1 and p53 in 32 HCC samples and their surrounding liver tissues and 5 normal liver tissues was detected respectively.

The expression level of WAF1 mRNA in HCC samples was lower than that in paratumor liver tissues(1.06 U +/- 0.37 U vs 1.30 U +/- 0.37 U, P < 0.01) and its positive rate of p21WAF1 was also lower than that in paratumor liver tissues(53.1% vs 100%, P < 0.01). The expression level of WAF1 mRNA in HCC samples with intra-hepatic metastatic lesions was lower than that without intra-hepatic metastatic lesions(0.92 U +/- 0.33 U vs 1.24 U +/- 0.35 U, P < 0.01) and its positive rate of p21WAF1 was also lower than that without intra-hepatic metastatic lesions(33.3% vs 78.6%, P < 0.05). The expression level of WAF1 mRNA in HCC samples with p53 mutation was lower than that without p53 mutation (0.92 U +/- 0.28 U vs 1.16 U +/- 0.40 U, P < 0.05) and its positive rate of p21WAF1 was also lower than that without p53 mutation(15.4% vs 78.9%, P < 0.01). The percentage of cells in S-phase in p21WAF1-positive HCC samples was lower than that in p21WAF1-negative HCC samples(44.57% +/- 7.56% vs 51.83% +/- 8.51%, P < 0.01). However, no significant difference in expression of WAF1 mRNA and p21WAF1 in HCC samples was found in other clinical pathological parameters such as the degree of differentiation, the histological pattern, the size of tumors, the status of capsule in tumors and the formation of tumor thrombus of portal vein. The expression level of WAF1 mRNA in normal liver tissues was strikingly lower(0.17 U +/- 0.06 U), and the immunohistochemical staining of p21WAF1 in all normal liver tissues was positive(100%).

The expression of WAF1 gene in HCC is predominantly regulated by dependence on p53 and the reduced WAF1 expression may participate in the carcingenesis and progression of HCC and the mechanisms of infiltration and metastasis of HCC.