Graham S
J Natl Cancer Inst. 1984 Dec;73(6):1423-8.
A variety of in vitro and in vivo inquiries suggests that retinoids of various sorts may reduce the risk of cancer at various sites. Epidemiologic studies done by a number of different investigators similarly show a reduction in risk with increases in ingestion of vitamin A-containing diets. These reductions in risk are primarily of the squamous cell types of cancer: lung, larynx, mouth, cervix, and bladder cancers. Retinoids, particularly beta-carotene, may have a risk-reducing function for such sites. However, evidence has also been found that retinoids under certain conditions may increase the risk of prostate cancer as well as of Hodgkin's disease and leukemia. It is not an impossibility that, although beta-carotene could reduce risk under most circumstances, under certain other circumstances it could increase risk for different cancers. Obviously, more research is necessary, particularly with the carotenoids.
各种体外和体内研究表明，各类维甲酸可能降低不同部位患癌风险。许多不同研究者进行的流行病学研究同样显示，随着含维生素A饮食摄入量的增加，患癌风险降低。这些风险降低主要针对鳞状细胞癌类型：肺癌、喉癌、口腔癌、宫颈癌和膀胱癌。维甲酸，尤其是β-胡萝卜素，可能对这些部位具有降低风险的作用。然而，也有证据表明，在某些情况下，维甲酸可能会增加前列腺癌、霍奇金病和白血病的风险。虽然β-胡萝卜素在大多数情况下可能降低风险，但在某些其他情况下可能增加不同癌症的风险，这并非不可能。显然，还需要更多研究，尤其是针对类胡萝卜素的研究。
