[An attempt at using monoclonal antibodies to oncogene products]

Four mouse hybridoma cell lines rp12, rp28, rp35 and rp38 producing monoclonal antibodies (MoAbs) reactive with ras oncogene product p21 were established with the use of recombinant proteins as immunogens. Using immunofluorescence, avidin-biotin complex or peroxidase-antiperoxidase methods, the reactivity of rp12, rp28 and rp35 MoAbs was examined in fresh and paraformaldehyde- or formalin fixed tissues of malignant and benign lesions of the skin, lung, stomach, uterus and ovary. These MoAbs strongly reacted with most malignant melanomas, lung cancers, stomach cancers, colon cancers and adenomatous polyps, uterus cancers, and ovary cancers, while they weakly reacted with inflammatory lung tissues, stomach polyps and metaplastic tissues and cervical dysplastic lesions, and did not react with pigmented nevi. The cancers and colon adenomatous polyps showed a high positive cell ratio, with not only cytoplasmic but also membranous localization of the staining, while other tissues had a low positive cell ratio and cytoplasmic staining localization. The MoAbs rp12, rp28 and rp35 could therefore be helpful for differential diagnosis between cancers and benign lesions.