Batlle A M
Centro de Investigaciones sobre Porfirinas y Porfirias-CIPYP, CONICET-FCEN, UBA, Buenos Aires, Argentina.
J Photochem Photobiol B. 1993 Sep;20(1):5-22. doi: 10.1016/1011-1344(93)80127-u.
Porphyrins are the only and most powerful photosensitizers synthesized internally. To understand better the involvement of porphyrins in photosensitization reactions, the heme biosynthetic pathway is first described, as well as the main features of its regulation in both erythroid and hepatic cells. Most disorders of porphyrin metabolism, known as porphyrias, are characterized by porphyrin accumulation. A full discussion of these diseases, their classification and relevant biochemical and clinical signs are presented. Abnormalities in heme biosynthesis in disorders other than porphyrias, such as iron-deficient and sideroblastic anemias, lead poisoning, hereditary tyrosinemia, chronic renal disease and alcoholism, are briefly considered. A complete survey of the experimental research on the biosynthesis of porphyrins in tumors and of the important association between cancer and porphyrias is dealt with. The link to photodynamic therapy (PDT) emerges naturally and this is treated from the point of view of using porphyrins endogenously formed by the tumors for their localization and PDT. Finally, considering the nature of the alterations occurring in heme metabolism in tumors, and porphyrias and their ubiquity, a model is discussed where the abnormality of heme synthesis is involved in the initiating lesion of carcinogenesis. The model strongly predicts that the incidence of cancer will be high in cells with abnormal heme metabolism, suggesting that porphyric patients may be at greater risk of the development of cancer.
卟啉是体内合成的唯一且最有效的光敏剂。为了更好地理解卟啉在光敏化反应中的作用，首先描述血红素生物合成途径及其在红细胞和肝细胞中调控的主要特征。大多数卟啉代谢紊乱，即卟啉症，其特征是卟啉积累。本文对这些疾病、它们的分类以及相关的生化和临床症状进行了全面讨论。除卟啉症外，其他疾病如缺铁性贫血和铁粒幼细胞贫血、铅中毒、遗传性酪氨酸血症、慢性肾病和酒精中毒中血红素生物合成的异常也作了简要介绍。本文还全面综述了肿瘤中卟啉生物合成的实验研究以及癌症与卟啉症之间的重要关联。与光动力疗法（PDT）的联系自然浮现，本文从利用肿瘤内源性形成的卟啉进行肿瘤定位和光动力疗法的角度对此进行了探讨。最后，考虑到肿瘤、卟啉症中血红素代谢发生改变的性质及其普遍性，本文讨论了一个模型，其中血红素合成异常参与致癌作用的起始病变。该模型强烈预测，血红素代谢异常的细胞中癌症发病率会很高，这表明卟啉症患者可能患癌症的风险更大。
