THE POSSIBLE INVOLVEMENT OF TRANSFORMING GROWTH FACTOR-ALPHA, BUT NOT EPIDERMAL GROWTH-FACTOR, IN RAT-LIVER CARCINOGENESIS INDUCED BY N-DIETHYLNITROSAMINE

We have previously described that, concentration of EGF-like substances in the liver of rats with DEN-induced hepatocarcinogenesis increases and reaches its maximum in tumors (the data of radioreceptor assay). This method does not give any information about what namely polypeptides (EGF or TGFalpha) have been detected. In the present study, Western immunoblot analysis of extracts from testing samples of liver with anti-TGFalpha or anti-EGF antiserums were used to identify immunoreactive TGFalpha and EGF. Our results indicate that EGF-competing substances from the liver tissues obtained at the different stages of DEN-induced carcinogenesis and control liver is immunoreactive with anti-TGFalpha antiserum but is immunologically unrelated to EGF. Possible mechanisms of involvement of TGFalpha in hepatocarcinogenesis are discussed.