The classical function of Vitamin D, which involves mineral balance and skeletal maintenance, has been known for many years. With the discovery of vitamin D receptors in various tissues, several other biological functions of vitamin D are increasingly recognized and its role in many human diseases like cancer, diabetes, hypertension, cardiovascular, and autoimmune and dermatological diseases is being extensively explored. The non-classical function of vitamin D involves regulation of cellular proliferation, differentiation, apoptosis, and innate and adaptive immunity. In this review, we discuss and summarize the latest findings on the non-classical functions of vitamin D at the cellular/molecular level and its role in complex human diseases.

Background: Vitamin D is a secosteroid, which was initially known for its skeletal role; however, in recent years, its functions in different organs have been increasingly recognized. In this review, we will provide an overview of vitamin D functions in the skin physiology with specific focus on its role in certain inflammatory skin conditions such as psoriasis and atopic dermatitis. Methods: A comprehensive literature search was carried out in PubMed and Google Scholar databases using keywords like “vitamin D,” “skin,” “atopic dermatitis,” and “psoriasis.” Only articles published in English and related to the study topic were included in this review. Results: Vitamin D is integrally connected to the skin for its synthesis, metabolism, and activity. It regulates many physiological processes in the skin ranging from cellular proliferation, differentiation, and apoptosis to barrier maintenance and immune functions. Vitamin D deficiency is associated with the risk of psoriasis and atopic dermatitis, and several clinical/observational studies have suggested the beneficial effect of vitamin D in the therapy of these 2 inflammatory skin disorders. Conclusions: Vitamin D exerts a pleiotropic effect in the skin and could be an important therapeutic option for psoriasis and atopic dermatitis.

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Genetic variants in micro-RNAs (miRNA) have been shown to affect progression, diagnosis, and prognosis of various malignancies; however, their role in esophageal squamous cell carcinoma (ESCC) susceptibility is controversial. Therefore, we aimed to determine role of common genetic variants in cancer related pre-miRNA in susceptibility and survival outcome of north Indian ESCC patients. We genotyped four common polymorphisms in pre-miRNA: mir-196a-2C>T, mir-146aG>C, mir-499T>C, and mir-423C>A in 289 incident ESCC cases (including 153 follow-up cases) and 309 controls using PCR/PCR RFLP-based methods. Binary logistic regression was applied for risk estimation, while Kaplan-Meier and Cox Regression tests were performed for survival analysis. We observed that none of the pre-miRNA genetic variants were associated with ESCC or its clinical phenotypes independently, however, combined risk genotypes of four pre-miRNA polymorphisms increased risk of ESCC in dose-response manner (Ptrend = 0.011). Specifically, patients with 2-4 risk genotypes of pre-miRNA polymorphisms had 1.4-fold higher risk of ESCC compared to patients with 0-1 risk genotypes (OR = 1.43, 95% CI = 1.02-1.09, P-value = 0.037). The risk was more pronounced in ESCC cases with upper-third esophageal tumors. Moreover, cumulative but not independent effect of risk genotypes of pre-miRNA polymorphisms was observed on survival outcome of ESCC patients. Cases with 2-4 risk genotypes had significantly lower median survival (11.60 vs. 30.2 months) and 2.3-fold greater hazard of death compared to patients with 0-1 risk genotypes. In conclusion, the four studied common pre-miRNA polymorphisms cumulatively affect susceptibility and survival of ESCC patients in north Indian population. © 2012 Wiley Periodicals, Inc.

Genetic variants in p53 and in its homologue p73 may modulate Esophageal Cancer (EC) risk because they are supposed to influence cell cycle progression, apoptosis and DNA repair. Therefore, we aimed to evaluate the association of p53 intron3 16 bp duplication and p73 G4C14-to-A4T14 polymorphisms with susceptibility to EC in a northern Indian population in 255 EC patients and 255 age and sex matched healthy controls. We found that p53 intron3 16 bp duplication polymorphism was not associated with EC and its clinical characteristics. However, p73 G4C14-to-A4T14 polymorphism was associated with significant higher risk of EC (OR = 1.74, 95% CI = 1.16-2.60, P = 0.007) in an allele dose-dependent manner (P(trend) = 0.0047). Stratification of subjects on the basis of clinical characteristics showed that p73 AT genotype carriers were at significant increased risk of developing esophageal squamous cell carcinoma (OR = 1.78, 95% CI = 1.18-2.67, P = 0.006) at middle third tumor location (OR = 1.87, 95% CI = 1.18-2.97, P = 0.007) with lymph node metastasis (OR = 1.77, 95% CI = 1.04-3.02, P = 0.035). No interaction with environmental risk factors was observed with any of the studied polymorphisms. In summary, p73 G4C14-to-A4T14 polymorphism but not the p53 intron3 16 bp duplication polymorphism is associated with EC and its clinical characteristics in northern Indian population.