[Synthesis and distribution of oncoproteins in tumor tissue]

Expression of myc, fos, src, ras and sis oncoproteins was studied in biopsy material of tumors, metastases and "normal" surrounding tissues from patients with different histological types of stomach and lung cancer, melanoma and other malignancy using immunoblotting. Besides, the immunohistochemical distribution of these oncoproteins under lung cancer and precancer conditions was analysed. The oncoproteins expression was significantly higher in cancer as compared with precancer and "normal' surrounding tissues. C-myc and c-fos gene products were detected in all the malignant tissues irrespectively to histogenesis of tumors, while the level of c-myc expression was rather high. The high level of c-fos expression was observed in stomach carcinomas and at early stages of lung tumor progression. C-src and c-sis genes expression varied in tumors of different histogenesis. C-src proteins were found in 60% of lung cancer but it was practically absent in stomach carcinomas and in melanomas. C-sis gene product was observed in some melanomas and lung carcinomas. Ras gene can be activated at early stages of tumor progression of stomach carcinomas and lung adenocarcinomas and at later stages of tumor progression in melanomas and small-cell lung carcinomas. Thus, there are some correlations between oncoprotein expression and tumor tissue histogenesis and progression.