It is widely accepted that chronic
inflammation initiates and promotes
carcinogenesis and
tumor progression in various cell types. However, this paradigm has not been comprehensively investigated in
melanoma. To investigate the effects of chronic
inflammation on the progression of
melanoma, we established a murine inflammatory skin model and investigated the relationship between skin
inflammation and
melanoma progression. In a murine model, B16F10
melanoma cells in inflamed skin grew significantly more rapidly than cells in control skin. The stromal expression of
periostin was upregulated in inflamed skin, and significantly more CD163⁺ M2 macrophages were recruited to the
melanomas in inflamed skin. We then immunohistologically examined the expression of stromal
periostin and the infiltration of CD163⁺ M2 macrophages in human acral lentiginous
melanomas (n = 94) and analyzed the statistical associations with clinicopathological variables. In human
melanomas, high
periostin expression and a large number of infiltrated M2 macrophages were significantly correlated with poor prognosis. Furthermore, we confirmed that
periostin promotes the proliferation of murine and human
melanoma cells in vitro. Our findings indicate that
periostin and M2 macrophages play a critical role in
melanoma progression and prognosis in both humans and mice, indicating that
periostin is a potential target for treating progressive
melanoma.