BG8 Lewis Y, also known as Lewis Y blood antigen or Lewis Y F3 or simply BG8, is a blood group antigen that is found on the Type 2 blood group oligosaccharides of glycolipids and glycoproteins. BG8 Lewis Y has been identified in many studies as a potential marker for differentiation between pulmonary adenocarcinoma (PACA) and epithelioid mesothelioma (EM). It has been reported that sensitivity of non-mesothelial antigens for adenocarcinoma is organ-dependent. When attempting to differentiate epithelioid mesothelioma from adenocarcinoma, BG8 Lewis Y performed at a sensitivity of 98% in the breast cancer group, and 100% in the lung cancer group. . It has been detected in large bowel tumors and colorectal carcinomas. It may be useful in the classification of human renal and bladder tumors and is being investigated as a diagnostic marker for several forms of cancer.