Immunohistochemistry for CK Pan (Pan-Cytokeratin) aims to detect a broad range of keratin proteins (intermediate filaments) present in most epithelial cells and their carcinomas. It uses a cocktail of antibodies (e.g., AE1/AE3) to recognize multiple keratin types, making it highly sensitive for detecting Carcinoma and excluding Sarcoma, Lymphoma, or Melanoma.