α-Carotene is a precursor of vitamin A that has been found in various fruits and vegetables. It inhibits proliferation of GOTO human neuroblastoma cells more potently than β-carotene and halts the cell cycle at the G0/G1 phase concomitantly with a reduction in the mRNA expression of the protooncogene N-Myc. It is also more potent than β-carotene in mouse models of skin and lung carcinogenesis and decreases the number of hepatomas in mice with spontaneous liver carcinogenesis when administered in drinking water at a concentration of 0.05%. α-Carotene levels are increased in patients with coronary heart disease and are inversely correlated with the risk of estrogen receptor-negative breast cancer.
