ACCUMULATION OF BETA-CAROTENE IN NORMAL COLORECTAL MUCOSA AND COLONICNEOPLASTIC LESIONS IN HUMANS

The quantity of beta-carotene (BC) accumulated in colonic polyps and c olonic cancererous tissue in humans in situ was determined relative to the quantity accumulated in normal colon and rectal tissue. Serum con centration of BC, retinol, and alpha-tocopherol and tissue BC concentr ation were determined by high-performance liquid chromatography in sam ples obtained before and after oral supplementation with BC (30 mg/day ). The serum BC and retinol concentrations significantly increased in response to supplementation in control, polyp, and cancer patients, bu t there was no change in serum alpha-tocopherol concentration. The BC concentration in tissue (colon, rectum, and tumor) of cancer patients was significantly less than that in tissue samples from control and po lyp patients. Relative to baseline values, BC accumulated to a signifi cant extent in tissues from all patients, including polyp and tumor ti ssue, during supplementation. The results indicate that BC does accumu late in colonic neoplastic tissue in humans and may potentially be uti lized to augment cytotoxicity of chemotherapeutics or to prevent malig nant transformation of cells.