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 .AE1/AE3 is a mixture of both AE1 and AE3, whereas AE1 reacts with type I cytokeratins and AE3 with type II cytokeratins. AE1/AE3 is a widely used as pan-cytokeratin marker. It is positive in all epithelial tumours but few epithelial tumours are negative or weakly positive for this cocktail such as hepatocellular and renal cell carcinoma, adrenal cortical carcinoma, prostatic adenocarcinomas, and neuroendocrine tumours.