Immunohistochemical Expression of p53, p21, and mdm2 Proteins in Human Papillomavirus Positive and Negative Invasive Uterine Cervical Carcinomas

ABSTRACT

BACKGROUND: In the uterine cervical carcinoma, the inactivation of p53 protein by human papillomavirus(HPV) E6 protein has been reported to play a greater role in carcinogenesis than the mutation of the p53 gene. Therefore, the mutation of the p53 gene is rare. p21 and mdm2 proteins are induced by wild-type p53 protein and are involved in the cell cycle regulatory mechanism. METHODS: Immunohistochemical staining for p53, p21 and mdm2 proteins was performed in 26 HPV-positive and 13 HPV-negative invasive cervical carcinomas together with 5 non-neoplastic cervical tissues. RESULTS: The frequencies of the expression of p53, p21 and mdm2 proteins were 82.1%, 84.6% and 66.7%, respectively. The expression of p53 protein was less frequently demonstrated in HPV-positive cases than HPV-negative cases, which was statistically a negative correlation(p=0.018). The expression of p53 and p21 proteins was statistically significant(p=0.000). CONCLUSIONS: p53, p21 and mdm2 proteins were highly expressed in both HPV-positive and HPV-negative cervical carcinomas. Significantly higher expression of p53 protain in HPV-negative cases necessitate a further study for investigating the role of p53 protein accumulation in carcinogenesis of HPV-negative cervical carcinomas. The relationship between the expression of p53 protein and p21/mdm2 proteins may indicate that p21 and mdm2 proteins also have a role in carcinogenesis, where p53 protein plays a fundamental role.