Immunohistochemical detection of the Ca antigen in normal and tumor tissues of humans by use of Ca1 monoclonal antibody.

The Ca1 monoclonal antibody was used to detect Ca antigen in paraffin sections with the use of a two-stage indirect immunoperoxidase technique. A range of normal and malignant human tissues was examined. The antibody reacted with squamous cell carcinomas, small cell carcinomas, adenocarcinomas, ductal carcinomas, and anaplastic carcinomas from gastrointestinal, lung, and breast tissues. Melanomas were negative. Reactivity was also observed against normal tissues: urinary transitional epithelium, fallopian tube epithelium, breast ducts, sweat glands, sebaceous glands, alveolar epithelium, bile duct, gallbladder, kidney tubules, and some digestive tract epithelial cells. Although the study confirms earlier reports that Ca1 is a marker for some normal, nonciliated epithelial cells and for epithelial and some other cancers, a more widespread distribution for normal tissues was found.