Histological analysis is crucial for diagnosing GI cancers. Tissue samples obtained via biopsy or surgical resection are processed and stained (commonly with hematoxylin and eosin) to examine cellular morphology. Special stains and immunohistochemistry are also used to identify specific markers that aid in the diagnosis. For example, CK7 and CK20 staining patterns help differentiate between various adenocarcinomas.
