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1、1（摘自 45 度角 F3 http:/www.cc98.org/dispbbs.asp?BoardID=241 DOI: 10.1002/cncr.23867.Individuals with the BsmI polymorphism had a 30% increase in the odds ratio for melanoma, Simone Mocellin, M.D., Ph.D., and Donato Nitti, M.D., of the University of Padova, reported online in Cancer. Another vitamin D r

2、eceptor polymorphism previously implicated in melanoma had no association with the cancer. Data were inconclusive regarding three additional polymorphisms. “Current evidence is in favor of the association between one vitamin D receptor gene polymorphism and the risk of melanoma development, although

3、 further work will be necessary to validate the risk identified in the current meta-analysis,“ the authors concluded. A growing body of evidence suggests that vitamin D - specifically 1,25-dihydroxycholecaliciferol (1,25OH2D3) - has significant protective effects against cancer. Much of the interest

4、 in vitamin Ds anticancer potential centers on its role as a transcription factor involved in regulating cell growth, differentiation, and apoptosis, the authors said. Epidemiologic evidence has suggested an inverse association between sun exposure, serum levels of 1,25OH2D3, and vitamin D intake an

5、d the risk of developing or surviving cancer, they continued. “Because this vitamin exerts its function on engagement of its receptor . it is likely that polymorphisms of this nuclear hormone receptor family member affect the ability of interacting with its ligand, which ultimately would lead to dif

6、ferent levels of vitamin D biologic activity,“ said Drs. Mocellin and Nitti. Studies of specific polymorphisms have yielded conflicting results, and the total body of data had not been examined by meta-analytic techniques, they added. In an effort to fill in some of the gaps in the information, the

7、authors analyzed data from six studies that investigated associations between melanoma and five vitamin D polymorphisms: TaqI, FokI, BsmI, EcoRV, and Cdx2. Collectively, the studies comprised 2,152 cases and 2,410 controls. 2Three of the six studies investigated the BsmI restriction fragment length

8、polymorphism. The studies demonstrated homogeneity in three different odds ratio analyses. Logistic regression analysis suggested a significant association between the polymorphism and melanoma (P=0.02). A pooled analysis of genotype data provided further evidence of the association (P=0.002). Sever

9、al investigators had proposed the FokI polymorphism as a contributor to melanoma risk. Two of four studies that examined the polymorphism found an association. However, meta-analysis failed to reveal a significant role for the polymorphism in melanoma risk. Data for the remaining three polymorphisms

10、 could not be analyzed adequately because of conflicting findings or between-study heterogeneity that precluded meta-analysis. The authors said their findings are consistent indirectly with the hypothesis that the BsmI polymorphism alters interaction between 1,25OH2D3 and the vitamin D receptor, the

11、reby reducing 1,25OH2D3 levels or activity and increasing vulnerability to melanoma. They pointed out, however, that there is no current evidence of a functional effect of the polymorphism on vitamin D metabolism or the vitamin D receptor. They also noted that “a significant limitation of the curren

12、t meta-analysis is that the results could not be adjusted by patient characteristics (eg. age, sex), environmental factors (eg. sun exposure, dietary vitamin D intake), or any other melanoma risk factors (eg. phototype, skin/eye color). Conversely, only an individual patient data meta-analysis could address this issue,“ they said. 1. In the current analysis, how many vitamin D receptor polymorphisms had significant associations with melanoma risk?a. Oneb. Threec. All fived. None of them2. People with the BsmI polymorphism had an increased risk of melanoma. True or False?