A microRNA expression screen was performed analyzing 157 different microRNAs in laser-microdissected tissues from benign melanocytic nevi (n = 10) and primary malignant melanomas (n = 10), using quantitative real-time PCR. Differential expression was found for 72 microRNAs. Members of the let-7 family of microRNAs were significantly downregulated in primary melanomas as compared with benign nevi, suggestive for a possible role of these molecules as tumor suppressors in malignant melanoma. Interestingly, similar findings had been described for lung and colon cancer. Overexpression of let-7b in melanoma cells in vitro downregulated the expression of cyclins D1, D3, and A, and cyclin-dependent kinase (Cdk) 4, all of which had been described to play a role in melanoma development. The effect of let-7b on protein expression was due to targeting of 3′-untranslated regions (3′UTRs) of individual mRNAs, as exemplified by reporter gene analyses for cyclin D1. In line with its downmodulating effects on cell cycle regulators, let-7b inhibited cell cycle progression and anchorage-independent growth of melanoma cells. Taken together, these findings not only point to new regulatory mechanisms of early melanoma development, but also may open avenues for future targeted therapies of this tumor.

Psoriasis is a multifactorial skin disease characterized by epidermal hyperproliferation and chronic inflammation, the most common form of which is psoriasis vulgaris (PsV). We present a genome-wide association analysis of 2,339,118 SNPs in 472 psoriasis patients and 1,146 controls from Germany, with follow-up of the 147 most significant SNPs in 2,746 PsV cases and 4,140 controls from three independent replication panels. We identified an association at TRAF3IP2 on 6q21 and genotyped two SNPs at this locus in two additional replication panels (the combined discovery and replication panels consisted of 6,487 cases and 8,037 controls; combinded P = 2.36×10−10 for rs13210247 and combined P = 1.24×10−16 for rs33980500). About 15% of psoriasis cases develope psoriatic arthritis (PsA). A stratified analysis of our datasets including only PsA cases (1,922 cases compared to 8,037 controls, P=4.57×10−12 for rs33980500) suggested that TRAF3IP2 represents a shared susceptibility for PsV and PsA. TRAF3IP2 encodes a protein involved in IL-17 signaling and which interacts with memebers of the Rel/NF-κB transcription factor family.

Psoriasis vulgaris (PsV) is a common inflammatory and hyperproliferative skin disease. Up to 30% of people with PsV eventually develop psoriatic arthritis (PsA), an inflammatory musculoskeletal condition. To discern differences in genetic risk factors for PsA and cutaneous-only psoriasis (PsC), we carried out a genome-wide association study (GWAS) of 1,430 PsA case subjects and 1,417 unaffected control subjects. Meta-analysis of this study with three other GWASs and two targeted genotyping studies, encompassing a total of 9,293 PsV case subjects, 3,061 PsA case subjects, 3,110 PsC case subjects, and 13,670 unaffected control subjects of European descent, detected 10 regions associated with PsA and 11 with PsC at genome-wide (GW) significance. Several of these association signals (IFNLR1, IFIH1, NFKBIA for PsA; TNFRSF9, LCE3C/B, TRAF3IP2, IL23A, NFKBIA for PsC) have not previously achieved GW significance. After replication, we also identified a PsV-associated SNP near CDKAL1 (rs4712528, odds ratio [OR] = 1.16, p = 8.4 × 10(-11)). Among identified psoriasis risk variants, three were more strongly associated with PsC than PsA (rs12189871 near HLA-C, p = 5.0 × 10(-19); rs4908742 near TNFRSF9, p = 0.00020; rs10888503 near LCE3A, p = 0.0014), and two were more strongly associated with PsA than PsC (rs12044149 near IL23R, p = 0.00018; rs9321623 near TNFAIP3, p = 0.00022). The PsA-specific variants were independent of previously identified psoriasis variants near IL23R and TNFAIP3. We also found multiple independent susceptibility variants in the IL12B, NOS2, and IFIH1 regions. These results provide insights into the pathogenetic similarities and differences between PsC and PsA.

To identify novel psoriasis susceptibility loci, we carried out a meta-analysis of two recent genome-wide association studies 1,2, yielding a discovery sample of 1,831 cases and 2,546 controls. 102 of the most promising loci in the discovery analysis were followed up in a three-stage replication study using 4,064 cases and 4,685 controls from Michigan, Toronto, Newfoundland, and Germany. Association at a genome-wide level of significance for the combined discovery and replication samples was found for three genomic regions. One contains NOS2 (rs4795067, p = 4 × 10−11), another contains FBXL19 (rs10782001, p = 9 × 10−10), and a third contains PSMA6 and NFKBIA (rs12586317, p = 2 × 10−8). All three loci were also strongly associated with the subphenotypes of psoriatic arthritis and purely cutaneous psoriasis. Finally, we confirmed a recently identified3 association signal near RNF114.

Purpose:To better understand the molecular mechanisms of malignant melanoma progression and metastasis, gene expression profiling was done of primary melanomas and melanoma metastases. Experimental Design: Tumor cell^specific gene expression in 19 primary melanomas and 22 melanoma metastases was analyzed using oligonucleotide microarrays after laser-capture microdissection of melanoma cells. Statistical analysis was done by random permutation analysis and support vector machines. Microarray data were further validated by immunohistochemistry and immunoblotting. Results: Overall, 308 genes were identified that showed significant differential expression between primary melanomas and melanoma metastases (false discovery rate V 0.05). Significantly overrepresented gene ontology categories in the list of 308 genes were cell cycle regulation, mitosis, cell communication, and cell adhesion. Overall, 47 genes showed up-regulation in metastases. These included Cdc6, Cdk1, septin 6, mitosin, kinesin family member 2C, osteopontin, and fibronectin. Down-regulated genes included E-cadherin, fibroblast growth factor binding protein, and desmocollin 1 and desmocollin 3, stratifin/14-3-3r, and the chemokine CCL27. Using support vector machine analysis of gene expression data, a performance of >85% correct classifications for primary melanomas and metastases was reached. Further analysis showed that subtypes of primary melanomas displayed characteristic gene expression patterns, as do thin tumors (V1.0 mm Breslow thickness) compared with intermediate and thick tumors (>2.0 mm Breslow thickness). Conclusions: Taken together, this large-scale gene expression study of malignant melanoma identified molecular signatures related to metastasis, melanoma subtypes, and tumor thickness. These findings not only provide deeper insights into the pathogenesis of melanoma progression but may also guide future research on innovative treatments.The incidence of malignant melanoma is steadily increasing with a present lifetime risk of 1 in 75 among the Caucasian population (1). The underlying factors for this phenomenon are largely unknown. After diagnosis of malignant melanoma, the single most important factor for the prognosis of melanoma patients is vertical tumor thickness as described earlier by Breslow (2). It could be shown that tumors of a few-millimeter thickness already show a high potential for metastasis with a fatal outcome for the patient. In the metastatic stage, melanoma patients have only few treatment options, consisting of monochemotherapies with dacarbazine (DTIC) or temozolomide, or polychemotherapy regimens combining DTIC with other chemotherapeutic agents such as cisplatin and 1,3-bis(2-chloroethyl)-1-nitrosourea (3 -5). Although significant clinical response rates were achieved by these treatment modalities, there was no substantial effect on the overall survival of these patients. Unfortunately, little is known about factors that contribute to the process of melanoma progression and metastasis.In recent years, DN...