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 (of all basic histological types - squamous cell, neuroendocrine, adenocarcinoma, undifferentiated). Simultaneously the relation of tumor immunophenotype and level of differentiation, cell death and 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 of p53 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. Positivity of 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 and undifferentiated carcinomas. The level of bcl-2 expression in squamous cell carcinomas was found higher than in references. Among tumors with cell death there was an inverted relation of bcl-2 and 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 tumors and newly for p53 positive squamous cell carcinomas. Evaluation of the expression of p53, p21 and bcl-2 in lung carcinomas is so equivocal that its prognostic 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 level of tumor - tumors with cell death - survival