Increased expression of a putative adenoma-associated antigen in pre-colonoscopic effluent of patients with colorectal cancer.

A monoclonal antibody Adnab-9, was raised against antigens derived from benign polyps of the colon. Adnab-9 was tested against pre-colonoscopic effluent material obtained from groups of patients with a macroscopically normal colonscopic examination, histologically confirmed adenomatous polyps and patients with colorectal cancer (CRC). The resultant binding levels displayed little overlap between the CRC group and the normal, and the difference was statistically significant. Since this putative early neoplasia associated antigen is essentially not expressed in CRC extracts, it may originate from a region of the colon predisposed to neoplasia, increasing in expression as the tendency to malignancy progresses, useful in the diagnosis of early stage malignancy.