H-ras p21 and peanut lectin immunoreactivity of hyperplastic, preneoplastic and neoplastic urinary bladder lesions in rats.

Hyperplastic, preneoplastic and neoplastic urinary bladder lesions induced by bladder carcinogens and toxins in the rat were evaluated for immunoreactivity with polyclonal or monoclonal antibodies to H-ras p21 or binding to peanut lectin with avidin-biotin immunocytochemistry. A low proportion (less than 20%) of hyperplastic and neoplastic bladder lesions induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine and fixed in Bouin's fixative only were immunoreactive on the cell membrane with the antibodies to H-ras p21. Lectin binding was found for these lesions, as well, even in formalin-fixed tissue and for lesions induced by other carcinogens, but not in regenerative bladder hyperplasias after cyclophosphamide exposure or in bladder exposed to bladder tumor promoters. The latter lesions were also not immunoreactive with antibodies to p21. Our results suggest that this relatively simple technique might be used for identification and screening of tumors for involvement of ras oncogenes and carcinogen initiation.