Sex difference in cellular retinol- and retinoic acid-binding proteins in human colon adenocarcinomas

Human colon adenocarcinomas and adjacent non-cancerous, normal colon from the same patient were assayed for the presence and amounts of cellular binding proteins for retinol (CRBP) and retinoic acid (CRABP) by sucrose gradient analysis. In male patients, the mean concentrations of both CRBP and CRABP in the colon cancers were statistically significantly higher than in the adjacent normal colon. By contrast, in female colon cancers, the mean levels for both binding proteins were reduced approximately 2-fold, compared to the concentrations in the adjacent normal colon. These findings reveal an unexpected sex difference in the binding proteins for retinol and retinoic acid in human colon malignancies.