Infundibular hyperkeratosis, hyperplasia of the follicular epithelium and perifolliculitis are major histopathological characteristics of hidradenitis suppurativa/acne inversa. These apparently precede rupture of the follicle. In particular, hyperplasia of the follicular epithelium probably marks the beginning of sinus formation, which usually spreads horizontally. Psoriasiform hyperplasia of the interfollicular epidermis with subepidermal inflammatory infiltrate might be interpreted as an inflammation-driven process basically identical to that which is evident at the terminal follicle. However, it does not lead to harmful and progressive sequelae like those (rupture, sinus tracts) seen at the terminal follicles.
Purpose: Cancers have developed a number of strategies to escape immune responses including the differential expression of costimulatory molecules of the B7 family. B7-H3 and B7-H4 have recently been described in different tumor entities but the relevance for melanoma has not yet been studied so far.Experimental Design: Using immunohistochemistry, B7-H3 and B7-H4 expression was studied on 29 melanoma lesions. Survival curves and log-rank tests were used to test the association of protein expression with survival. Cell lines were evaluated for B7-H3 and B7-H4 expression by PCR and flow cytometry. Functional T-cell-tumor coculture assays were carried out with in vitro generated tumor transfectants.Results: B7-H3 and B7-H4 expression was detected in primary tumor lesions (29 of 29 and 28 of 29) and in metastases (28 of 29 and 26 of 29). The numbers of CD68 þ macrophages were significantly lower in patients with low B7-H4 expression, whereas CD8 þ T-cell infiltrates were independent of expression levels.Furthermore, a survival benefit for patients with B7-H4 low expressing melanoma was found, whereas B7-H3 was not associated with any clinical parameter. All 23 melanoma cell lines analyzed expressed B7-H3 and B7-H4 mRNA and protein, but B7-H4 was restricted to intracellular compartments. On silencing of B7-H3 by specific shRNA tumor-associated antigen-specific T cell responses were unaltered. Overexpression of B7-H4 on melanoma cells did not alter the cytotoxicity of different CD8 þ effector cells, but drastically inhibited cytokine production. Conclusions: Our study provides for the first time evidence of B7-H4 expression on melanoma cells as a mechanism controlling tumor immunity which is associated with patients' survival. Clin Cancer Res; 17(10); 3100-11. Ó2011 AACR.
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