An antitumor antibody in normal human serum: reaction of anti-T with breast carcinoma cells.

Carcinoma of the breast is now the most common malignant disease of females in Europe and North America. The most critical single factor in determining the success or failure of treatment is the extent of the disease at diagnosis. A sensitive immunoperoxidase technique was utilized to (1) detect the presence in normal human serum of antibody directed against breast carcinoma cells (anti-T antibody), and (2) determine whether this antibody could be used to discriminate between benign and malignant breast epithelium in sections of formalin-fixed, paraffin-embedded tissue. A total of 11 benign and 11 malignant breast lesions were examined for evidence of binding of human immunoglobulin, before and after application of purified anti-T antibody or normal human AB serum (containing anti-T antibody). Malignant cells showed significant binding of human immunoglobulin (anti-T); benign or normal cells did not. Clear immunohistological separation of benign and malignant breast lesions appears to be potentially feasible by this method.