ASSESSMENT OF P53 EXPRESSION IN NASOPHARYNGEAL CARCINOMA

We analyzed the expression of the p53 protein by immunohistochemical m ethods from 101 patients with nasopharyngeal carcinoma (NPC): 24 with NPC and dysplastic lesions adjacent to carcinoma and 14 with primary a nd metastatic specimens. Ninety-six of 101 lesions (95%) had detectabl e p53 protein in the nuclei of tumor cells, indicating that overexpres sion of the p53 protein might be closely associated with NPC. Among 24 patients who had NPC and dysplastic lesions adjacent to carcinoma, 19 of the dysplastic lesions (79.2%) and 22 of the carcinomas (91.7%) sh owed positive staining for the p53 protein. In dysplastic epithelia p5 3 antigenicity was generally in a basal location. The significant asso ciation of p53 expression in NPC and dysplastic lesions adjacent to ca rcinoma (P < .0001, Fisher's exact probability test) suggests that p53 overexpression seems to occur at an early stage in the development of NPC. p53 expression in NPC does not correlate with histological gradi ng, degree of lymphocytic infiltration between tumor cells, clinical s tage, sex, or age (P > .05, chi-squared test). A comparison of p53 exp ression between primary and metastatic NPC was performed in 14 lesions . Although the p53 protein was consistently expressed in primary and m etastatic tumor cells, there was no significant difference in p53 expr ession in both distinct but related lesions (P > .05, paired t-test). Our results suggest that the association of overexpression of the p53 protein in NPC may not be indicative of a mutant type p53 protein. HUM PATHOL 26:380-386. Copyright (C) 1995 by W.B. Saunders Company