Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody. Carbohydrate antigen 125 (CA125) is a high molecular weight glycoprotein classified as mucin 16 (MUC-16). CA125 is normally expressed by glandular epithelium of different organs and is highly expressed in ovarian carcinomas . Serum CA125 is also used to monitor the progression of ovarian carcinoma. Among non-epithelial tumours, CA125 expression may be observed in epithelioid sarcoma and desmoplastic small round cell tumour.