The Role of Tennessee Antigen in the Diagnosis of Gastrointestinal Malignancy

Abstract

Tennessee antigen (TAG) is a glycoprotein which has been extracted from adenocarclnoma of the colon. It is one of the numerous tumour associated antigens whlch has been developed and there is evidence that it differs considerably from carcino-embryonic antigen (CEA) preparations. A commercial kit uslng a haemagglutlnatlon inhlbltion assay Is available and Its ability to discriminate between benign and malignant conditlons of the gastrointestinal tract has been studied, uslng 7.7 units/ml as the upper limit of normal. With upper gastrolntestinal disease, discrimination is comparable to that achieved with TAG by other workers and also to that achieved with CEA. For gastric carcinoma TAG has a sensitivity of 71% and a specificlty of 77%. With lower gastrointestinal tract disease discrimination was poor, TAG having a sensitivity of 76% but a specificity of 44% for colorectai carcinoma. Dlscriminatlon between pancreatic carcinoma and chronic pancreatitis was poor, TAG having a sensitivity of 100% for carcinoma and a specificity of 22%.