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In addition to producing sebum, sebocytes link lipid metabolism with inflammation at a cellular level and hence, greatly resemble adipocytes. However, so far no analysis was performed to identify and characterize the adipocyte-associated inflammatory proteins, the members of the adipokine family in sebocytes. Therefore, we determined the expression profile of adipokines [adiponectin, interleukin (IL) 6, resistin, leptin, serpin E1, visfatin, apelin, chemerin, retinol-binding protein 4 (RBP4) and monocyte chemoattractant protein 1 (MCP1)] in sebaceous glands of healthy and various disease-affected (acne, rosacea, melanoma and psoriasis) skin samples. Sebaceous glands in all examined samples expressed adiponectin, IL6, resistin, leptin, serpin E1 and visfatin, but not apelin, chemerin, RBP4 and MCP1. Confirming the presence of the detected adipokines in the human SZ95 sebaceous gland cell line we further characterized their expression and secretion patterns under different stimuli mimicking bacterial invasion [by using Toll-like receptor (TLR)2 and 4 activators], or by 13-cis retinoic acid (13CRA; also known as isotretinoin), a key anti-acne agent. With the exception of resistin, the expression of all of the detected adipokines (adiponectin, IL6, leptin, serpin E1 and visfatin) could be further regulated at the level of gene expression, showing a close correlation with the secreted protein levels. Besides providing further evidence on similarities between adipocytes and sebocytes, our results strongly suggest that sebocytes are not simply targets of inflammation but may exhibit initiatory and modulatory roles in the inflammatory processes of the skin through the expression and secretion of adipokines.

Background The formation of metastases and the efficacy of systemic therapies in cutaneous malignant melanoma (CMM) depend on the characteristics of the tumour cells and the host immune response. Aberrant expression of metallothionein (MT) has been observed in several types of cancers with poor prognoses. Objective To perform an immunohistochemical study on primary CMM comparing the MT expression of tumours without metastases (n = 23) to that of samples with haematogenous metastases (n = 23) and to examine the correlation between MT staining and immunological markers relevant in CMM progression. Methods The immunohistochemical labelling of different tumour sections was analysed using tissue microarrays for the evaluation of the suitability of this method in future studies. Results Our results suggest that MT overexpression is significantly more frequent in primary CMM with haematogenous metastases (P = 0.018) and that the overexpression is independent of the Breslow tumour thickness (R = 0.102, P = 0.501). Interestingly, MT overexpression of the tumour cells was correlated with the presence of tumour-infiltrating CD68+ macrophages (P = 0.003), a known predictive factor for melanoma progression, thereby suggesting a role for MT in the development of a defective host immune response. Furthermore, the presence of CD163+ macrophages infiltrating the tumours correlated with metastasis formation (P