Cellular binding proteins for vitamin A in human carcinomas and in normal tissues

Blinded analyses of the concentrations of binding proteins for retinol and retinoic acid (CRABP) in homogenates of cancer and normal tissue aliquots obtained from human cervix, endometrium, ovary, breast, and lung were carried out by the sucrose gradient ultracentrifugation technique. In carcinomas of the cervix and endometrium, CRABP mean values of 50.4 and 123.2 pmol/g tissue, respectively were detected. Such concentrations represent a 3- and 4-fold increase over the mean values of CRABP in the normal cervix (16.9 pmol/g) and normal endometrium (30.8 pmol/g), respectively. In carcinomas of the ovary, the mean CRABP level was 128.6 pmol/g compared to the maximal mean value of less than or equal to 0.46 pmol/g in the normal ovary. Elevated levels of CRABP were also found in breast and lung carcinomas compared to the amounts detected in the same patient in normal tissue aliquots of the same organ. The differences between CRABP concentrations in cervical, endometrial, ovarian, and breast carcinomas and those in normal tissue are statistically significant. In contrast, cellular retinol-binding protein concentrations were reduced in the endometrial, ovarian, breast, and lung carcinomas compared to normal tissues. There were no significant differences between the log-mean concentrations of cellular retinol-binding proteins in the cytosols from tissue aliquots of carcinoma of the cervix and those in the cytosols from tissue aliquots of normal cervix.