SUMMARY, EXPLANATION AND LIMITATIONS:
CA 72.4 or Tumor-associated glycoprotein 72 (TAG-72) is a high molecular weight glycoprotein that localizes to the cytoplasm and cell membrane of malignant cells. TAG-72 is expressed by 80% of colorectal carcinomas but is rarely expressed in normal epithelium and benign diseases. In addition, CA 72.4 is highly expressed by low-grade mucoepidermoid carcinomas but is absent in pure squamous cell mucoepidermoid carcinomas. With the exception of secretory endometrium, CA 72.4 expression is weak or nondetectable in normal adult tissues. is expressed by several gynecologic malignancies including common epithelial ovarian carcinomas and endometrial carcinomas. In human prostatic adenocarcinomas, CA 72.4 expression negatively correlates with the Gleason grade of differentiation. CA 72.4 is expressed by the majority of gastric, esophageal, pancreatic and non-small cell lung carcinomas. Finally, CA 72.4 is useful for purifying primary ovarian cancer cells from patient ascites.
Immunogen: Purified human CA 72.4 protein.
Staining pattern: Cell surface and cytoplasmic
Positive control: Tissue sample from colon carcinoma, breast carcinoma or lung carcinoma.
This antibody is designed for the specific localization of human calcitonin using IHC techniques in formalin-fixed, paraffin-embedded tissue sections.
Positive immunoreactivity was observed for adenocarcinomas from breast (85% of infiltrating ductal carcinomas), colon (85-90%), pancreas, stomach, esophagus, salivary glands (duct epithelial carcinomas, adenocarcinomas, papillary cystadenocarcinomas, low-grade mucoepidermoid carcinomas), ovary, endometrium, and lung (except small cell carcinomas). TAG-72 antigen is not expressed in leukemias, lymphomas, sarcomas, mesotheliomas and melanomas. In normal tissues from the above organs show slight or absent immunostaining except in proliferative phase endometrium, salivary gland epithelium and the colonic epithelium. In case of differential diagnosis between metastatic adenocarcinoma pleural and primary mesothelioma is recommended to include this antibody to immunohistochemical panel, because the positive immunostaining for CA 72.4 strongly suggests the first possibility and the second if is negative. In breast carcinoma the expression of TAG-72 is shown with prognostic value. Tumors with metastases to regional lymph nodes are negative for TAG-72 and clinically have more aggressive behavior.