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Reduced p21(WAF1/CIP1) expression and p53 mutation in hepatocellular carcinomas
1Pathology Division, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan.
Abstract:
p21(WAF1/CIP1) is a universal cyclin-dependent kinase (cdk) inhibitor, the expression of which is regulated by p53-dependent and p53-independent pathways. We examined p21(WAF1/CIP1) expression in and p53 status of 21 primary hepatocellular carcinomas (HCCs) by reverse-transcriptase polymerase chain reaction (RT-PCR) and by PCR single-strand conformation polymorphism (PCR-SSCP) analysis. p21(WAF1/CIP1) messenger RNA expression was reduced markedly in 8 of 21 HCCs (38.1%) and 5 of these 8 HCCs bore p53 mutations. The relative p21(WAF1/CIP1) messenger RNA expression value of HCCs with p53 mutations (.73 +/- .13 U, n = 6) was significantly lower than that of HCCs with wild-type p53 (1.00 +/- 0.21 U, n = 14; P < .01). The p21(WAF1/CIP1) expression levels in cancerous tissues (.73 +/- .13 U) were significantly reduced in comparison with those in noncancerous tissues (.97 +/- .13 U) (P < .01) in the 6 cases with p53 mutations. These data indicate that p21(WAF1/CIP1) expression in HCCs is predominantly regulated by dependence on p53 and that reduced p21(WAF1/CIP1 expression may participate in hepatocarcinogenesis.
Insights
Reduced p21 expression, a cyclin-dependent kinase inhibitor, is linked to p53 mutations in hepatocellular carcinoma (HCC). This suggests p53-dependent regulation of p21 plays a role in liver cancer development.
Area of Science:
- Oncology
- Molecular Biology
- Hepatology
Background:
- p21(WAF1/CIP1) is a key cyclin-dependent kinase (cdk) inhibitor.
- Its expression is controlled by both p53-dependent and independent pathways.
- Understanding p21 regulation is crucial for hepatocellular carcinoma (HCC) research.
Purpose of the Study:
- To investigate the relationship between p21(WAF1/CIP1) expression and p53 gene status in primary HCC.
- To determine if p53 mutations affect p21 expression levels in HCC tissues.
Main Methods:
- Analysis of p21(WAF1/CIP1) mRNA expression using reverse-transcriptase polymerase chain reaction (RT-PCR).
- Assessment of p53 gene status through PCR single-strand conformation polymorphism (PCR-SSCP) analysis.
- Comparison of p21 expression in cancerous versus non-cancerous tissues.
Main Results:
- Reduced p21(WAF1/CIP1) mRNA expression was observed in 38.1% of primary HCCs studied.
- A significant correlation was found between lower p21 expression and the presence of p53 mutations (P < .01).
- p21 expression was significantly lower in cancerous tissues compared to non-cancerous tissues in HCCs with p53 mutations (P < .01).
Conclusions:
- p21(WAF1/CIP1) expression in HCC is predominantly regulated by p53.
- Diminished p21 expression, potentially due to p53 mutations, may contribute to the development of hepatocellular carcinoma.
- These findings highlight the critical role of the p53-p21 pathway in hepatocarcinogenesis.