https://www.ncbi.nlm.nih.gov/pubmed/28403520 Abstract BACKGROUND: Male androgenetic alopecia (Androgenetic Alopecia) is the most common form of hair loss in men and is characterized by a distinct pattern of progressive hair loss starting from the frontal area and the vertex of the scalp. Although several genetic risk loci have been identified, relevant genes for Androgenetic Alopecia remain to be defined. OBJECTIVES: Herein, molecular biomarkers associated with premature Androgenetic Alopecia were identified through gene expression analysis using cDNA generated from scalp vertex biopsies of hairless/bald men with premature Androgenetic Alopecia and healthy volunteers. RESULTS: This monocentric study reveals that genes encoding mast cell granule enzymes, inflammatory and immunoglobulin-associated immune mediators were significantly over-expressed in Androgenetic Alopecia. In contrast, under-expressed genes appear to be associated with the Wnt/β-catenin and BMP/TGF-β signaling pathways. Although involvement of these pathways in hair follicle regeneration is well-described, functional interpretation of the transcriptomic data highlights different events that account for their inhibition. In particular, one of these events depends on the dysregulated expression of proopiomelanocortin (POMC), as confirmed by RT-qPCR and immunohistochemistry. In addition, lower expression of CYP27B1 in Androgenetic Alopecia subjects supports the notion that changes in vitamin D metabolism contributes to hair loss. CONCLUSION: This study provides compelling evidence for distinct molecular events contributing to alopecia that may pave way for new therapeutic approaches. This article is protected by copyright. All rights reserved.