OVEREXPRESSION OF C-MYC, RAS AND C-ERBB-2 ONCOPROTEINS IN CARCINOMA OF UNKNOWN PRIMARY ORIGIN

The role of oncogenes in carcinoma of unknown primary site (CUP) has n ot yet been elucidated. In the present study. the expression of the c- myc p65 ms p21 and c-erbB-2 p185 oncoproteins were studied by a 3-step immunoperoxidase technique in 26 cases of CUP. Positive immunoreactiv ity was observed in 96% of the cases for. c-myc, 92% for ras and in 65 % for c-erb-2, with at least half of tumor cells labelled in 85%, 92% and 58% respectively. The degree of staining intensity was considered moderate or strong in more than half of the cases for all oncogene pro ducts. In conclusion, our results showed that patients with CUP have a n extremely high overexpression of all three oncogenes studied Neverth eless, the biological role of these overexpressed oncoproteins, their relationship with different histological of clinical parameters and th eir diagnostic or prognostic value need further evaluation.