Expression of P53, P21 and bcl-2 in Prognostic Lung Carcinomas

Overview

Expression of suppressor genes 53 and bcl-2 as well as of protein p21 (partly induced by p53 gene)was analyzed in a group of 77 resection specimens and bronchial excision of lung carcinomas (ofall basic histological types - squamous cell, neuroendocrine, adenocarcinoma, undifferentiated).Simultaneously the relation of tumor immunophenotype and level of differentiation, cell deathand 2-year-survival of patients was evaluated.Gene p53 showed non-only an expected strong expression in squamous cell carcinomas but espe-cially in adenocarcinomas, which were newly characterized by exceptional hyperexpression ofp53 in lowly differentiated variants.Expression level of protein p21 and gene p53 was parallel only in adenocarcinomas and undiffe-rentiated carcinomas but discordant in squamous cell and neuroendocrine carcinomas. Positivityof p21 slightly prevailed in well-differentiated variants of the histological types but an exceptio-nal positivity was found even in all the undifferentiated carcinomas.Gene bcl-2 revealed a paradox of strong expression in lowly differentiated neuroendocrine andundifferentiated carcinomas. The level of bcl-2 expression in squamous cell carcinomas was foundhigher than in references. Among tumors with cell death there was an inverted relation of bcl-2and p53 expression (high/low) in neuroendocrine carcinomas but both of them were mostly nega-tive in squamous cell carcinomas.A more frequent 2-year-surival of squamous cell carcinomas was verified for bcl-2 positive tumorsand newly for p53 positive squamous cell carcinomas.Evaluation of the expression of p53, p21 and bcl-2 in lung carcinomas is so equivocal that itsprognostic usage was found to be only complementary to the direct immunohistochemical investi-gation of the growth activities.

Key words:
lung carcinoma - immunophenotypical expression - p53-p21-bcl-2 Differentiation levelof tumor - tumors with cell death - survival