Special AT-rich sequence-binding protein 2 (SATB2) is a recently described marker that functions as a nuclear matrix-associated transcription factor. It has been reported that SATB2, in combination with CK20, could identify almost all colorectal carcinomas, including poorly differentiated colorectal carcinomas. Upper gastrointestinal (GI) carcinomas and pancreatic ductal carcinomas are usually negative for SATB2, and ovarian carcinomas, lung adenocarcinomas, and adenocarcinomas from other origin are rarely positive for SATB2. Therefore, SATB2 is a good marker for identifying a carcinoma of colorectal origin when working on a tumor of unknown primary. It can help differentiate colorectal metastasis (SATB2+) from primary pulmonary adenocarcinoma of mucinous or enteric type (SATB2- but often CDX2+)\n