Evaluation of the Cal antibody in the diagnosis of invasive breast cancer

SUMMARY An evaluation of Cal antibody staining was performed on paraffin sections from 136 breast lesions (64 benign and 72 malignant). Although cytoplasmic staining was encountered significantly more often in malignant lesions, the false negative rate was 6*9 % and the false posi-tive rate 56 2%. Benign lesions which showed positive staining included gynaecomastia, cystic mastopathy and fibroadenomata. Various other monoclonal antibodies showed staining similar to Cal antibody. Cal antibody was observed to bind to epithelial membrane antigen-coated sepharose beads. The Ca antigen was extracted by Ashall et al from a segregant malignant hybridoma produced by fusion of diploid fibroblasts and malignant cells from a human cervical carcinoma. The monoclonal anti-body (Cal) to this antigen was reported to identify malignant cells. ' Binding of the antibody using the indirect immunoperoxidase technique was encoun-tered in the majority of malignant tumours teste