Expression of proteins in p53 (p14ARF-mdm2-p53-p21WAF/CIP1) pathway and their significance in exocrine pancreatic carcinoma

Abstract

To investigate the expression of p14(ARF), p53, mdm2 and p21(WAF/CIP1) proteins and their relationship in exocrine pancreatic carcinoma. Specimens of pancreatic carcinoma, adjacent non-neoplastic pancreatic tissue and pancreatic benign lesions were examined for p14(ARF), p53, mdm2 and p21(WAF/CIP1) protein expression by tissue microarray technique and immunohistochemistry. The expression of p14(ARF), p53, mdm2 and p21(WAF/CIP1) proteins in pancreatic carcinoma were 35.3% (59/167), 57.5% (96/101), 64.1% (107/167) and 39.5% (66/167) respectively. The expression of p53 proteins was increased in pancreatic carcinoma (P < 0.01), while the expression of p14(ARF) and p21(WAF/CIP1) proteins was reduced (P < 0.05), as compared with that in non-neoplastic pancreatic tissue. p21(WAF/CIP1) protein expression in pancreatic carcinoma significantly correlated with the age of patients and perineural invasion (P < 0.05). p53 protein expression correlated significantly with tumor differentiation, lymph node metastasis and perineural invasion (P < 0.05). Mdm2 protein expression correlated significantly with tumor differentiation (P < 0.05), while p14(ARF) protein expression correlated significantly with the age of patients and metastasis (P < 0.05). There was also statistic correlation between the expression of these four genes (P < 0.05). Overexpression of p53 and mdm2 and loss of p14(ARF) and p21(WAF/CIP1) expression may contribute to the pathogenesis of pancreatic carcinoma. These proteins play a critical role in cell cycle arrest and apoptosis after DNA damage through p14(ARF)-mdm2-p53-p21(WAF/CIP1) pathway. Detection of p53 and Mdm2 protein overexpression may be useful in evaluation of the aggressiveness of pancreatic carcinoma.