[Expression of p21(WAF1) and its relationship with p53 and PCNA protein in epithelial ovarian cancer].

Background & Objective: Recent researches manifested that down-regulation of p21(WAF1) had relationship with carcinogenesis and development in various tumors, but its association with epithelial ovarian cancer (EOC) was not clear. This study was designed to investigate the role of p21(WAF1) in the tumorigenesis and development of EOC and its relationship with p53 and proliferating cell nuclear antigen (PCNA) protein.
Methods: Fifty-five EOC tissues, 32 benign ovarian tumor tissues, and 30 normal ovarian tissues were collected. Reverse transcription polymerase chain reaction (RT-PCR) was applied to determine the p21(WAF1)mRNA expression. Immunohistochemistry was applied to examine the protein expression of p21(WAF1), p53, and PCNA. The relationship between the expression of these markers and the clinicopathological characteristics, prognosis of the patients was analyzed.
Results: The positive rates of p21(WAF1)mRNA in EOC, benign ovarian tumor, and normal ovary were 40%, 56.25%, and 73.33%, respectively (P=0.012). The positive rates of p21(WAF1) protein were 36.36%, 56.25%, and 80%, respectively (P=0.001). The positive expression rates of p21(WAF1)mRNA and its protein in EOC were lower than those of the other two groups, while the positive expression rates of p53 and PCNA protein in EOC were higher than those of the other two groups (P< 0.05). Expression of p21(WAF1)mRNA had positive relation to its protein, negative relation to PCNA protein, no relation to p53 protein, while expression of p21(WAF1) protein had negative relation to p53 and PCNA protein in EOC. Low-expression of p21(WAF1) protein was associated with advanced FIGO stage (P=0.032), but not with age, histological type, pathological grade, and remnant tumor (P >0.05). There was no relationship between p21(WAF1)mRNA and former parameters (P >0.05). Univariate analysis showed that the patients with low-expression of p21(WAF1)mRNA and p21(WAF1) protein had poor prognosis (P< 0.05).
Conclusion: p21(WAF1) is down-regulated in EOC. p21(WAF1) might be able to be used as a marker to predict the prognosis of patients with EOC.