The value of a monoclonal anti-epithelial antibody (mAB lu-5) in the differential diagnosis of tumors. Immunohistochemical study.

The usefulness of a monoclonal anti-epithelial antibody, mAB lu-5, was assessed in the histologic differential diagnosis of 102 formalin-fixed, paraffin-embedded tumors including various carcinomas, sarcomas and lymphomas. A variety of nontumorous tissues were also evaluated. Although mAB lu-5 failed to provide conclusive results in a few cases, in general, it was found to be a reliable immunohistochemical marker of tumorous and nontumorous epithelial cells. Immunostaining with mAB lu-5 did not distinguish between tumorous and nontumorous tissues and between benign and malignant tumors. Further work is required to clarify the significance of strong immunoreactivity noted in chorionic epithelium and pituitary corticotrophs.