CDH17 antibody (Cadherin 17 or LI-cadherin) is a novel oncogene which is involved in tumor invasion and metastasis and is expressed in intestinal epithelium (1,2). CDH17 is a highly specific marker in colon cancer (99/99, 100%) and is a more sensitive marker than CDX2 (93/99, 94%) and CK20 (91/99, 92%) (3). Overexpression of CDH17 (and conversely, underexpression of CDX2) correlates to poor prognosis in patients with epithelial ovarian cancer (1). CDH17 may be helpful for early diagnosis of Barrett’s esophagus (4). CDH17 has been shown to be a useful marker for distinguishing between primary urinary bladder adenocarcinoma and urothelial carcinoma with glandular differentiation (5). Note that it does not distinguish primary urinary bladder adenocarcinoma from colorectal adenocarcinoma secondarily involving the bladder (5).