De Fine Olivarius F, Lock-Andersen J, Larsen F G, Wulf H C, Crosby J, Norval M
Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Denmark.
Br J Dermatol. 1998 Jun;138(6):986-92. doi: 10.1046/j.1365-2133.1998.02264.x.
Urocanic acid (UCA) is a major chromophore for ultraviolet (UV) radiation in the skin. On UV exposure, the naturally occurring trans-isomer converts to the cis-isomer in a dose-dependent manner. Accumulating evidence indicates that cis-UCA acts as an initiator of the UV-induced suppression of certain skin immune functions. This immunomodulation is recognized as an important factor in the development of skin cancer. In this study, pigmentation and UCA isomers were measured in 29 patients with previous basal cell carcinoma (BCC), 23 patients with previous cutaneous malignant melanoma (MM), and 32 healthy controls. Measurements were performed on UV-exposed (forehead, upper back) and UV non-exposed (buttock) skin. No significant differences in pigmentation percentage, total UCA concentration, relative (%) or absolute (nmol/cm2) cis-UCA concentration were observed between the groups in any of the body sites studied. The net production of cis-UCA after irradiation with a single test UV dose was evaluated. The relative production of cis-UCA following irradiation was significantly higher in both cancer groups when compared with the control group, while no significant difference was found between the BCC and the MM patients.
尿刊酸（UCA）是皮肤中紫外线（UV）辐射的主要发色团。暴露于紫外线时，天然存在的反式异构体以剂量依赖的方式转化为顺式异构体。越来越多的证据表明，顺式UCA是紫外线诱导的某些皮肤免疫功能抑制的启动因子。这种免疫调节被认为是皮肤癌发生发展的一个重要因素。在本研究中，对29例既往有基底细胞癌（BCC）的患者、23例既往有皮肤恶性黑色素瘤（MM）的患者和32名健康对照者进行了色素沉着和UCA异构体的测量。测量在紫外线暴露部位（前额、上背部）和非紫外线暴露部位（臀部）的皮肤进行。在所研究的任何身体部位的各组之间，色素沉着百分比、总UCA浓度、相对（%）或绝对（nmol/cm2）顺式UCA浓度均未观察到显著差异。评估了单次测试紫外线剂量照射后顺式UCA的净生成量。与对照组相比，两个癌症组照射后顺式UCA的相对生成量均显著更高，而BCC患者和MM患者之间未发现显著差异。
