A correlation was recently shown between expression of the vitronectin receptor (VnR) and the tumorigenic capacity of cultured human melanoma cell lines. On the other hand, modulation of VnR expression by interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) was observed on different non-melanoma cell lines. We tested IFN-gamma, TNF-alpha and interleukin-2 (IL-2), which are presumably released by infiltrating leukocytes in the melanoma lesional environment, on three melanoma cell lines. The VnR expression was assessed using FACS analysis and radioimmunolabelling. The VnR did not show any modulation after treatment with any of the cytokines tested. By contrast, the expression of the intercellular adhesion molecule-1 (ICAM-1), tested as control, on five melanoma cell lines, was greatly enhanced by IFN-gamma and TNF-alpha. Thus, some host cytokines may preferentially induce melanoma cells to express ICAM-1 (which can increase host cytotoxic response against melanoma), other than the VnR (which instead might contribute to melanoma metastasis).