Immunologic escape and angiogenesis in human malignant melanoma

Abstract

Background Melanoma escape mechanisms include immunosuppressive and angiogenic cytokine production. Objective We sought to determine vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) expression by immunohistochemistry, and soluble circulating plasma levels of VEGF, bFGF, IL-10, and transforming growth factor-β2 in patients with different stages of melanoma. Methods Biopsy specimens from 42 patients with primary melanoma and 9 with cutaneous metastases were studied by immunohistochemistry. In another 46 patients with melanoma (8 stage I and II; 18, III; and 20, IV) and in 10 healthy control participants, bFGF, VEGF, IL-10, and transforming growth factor-β2 circulating levels were analyzed. Results bFGF was positive in 85% and VEGF in 47.5% of 42 primary melanomas. Of 10 patients with primary melanoma (Breslow depth 1.5-3 mm) 6 were VEGF positive and had metastases develop, whereas 4 were VEGF negative and had no metastases at 5 years of follow up. VEGF, bFGF, and IL-10 plasma levels in patients with stages III and IV melanoma were higher than the control group ( P < .05 and P < .01, respectively). An inverse relationship was found between VEGF and IL-10. Specifically, in 7 patients with IL-10 levels higher than 10 pg/mL, VEGF levels were less than 49 pg/mL ( P < .05); in 9 patients with VEGF levels higher than 100 pg/mL, IL-10 levels were less than 6.7 pg/mL ( P < .01). Conclusion VEGF expression in 1.5- to 3.0-mm Breslow depth melanomas may be considered as an unfavorable prognostic factor. Immunosuppressive (IL-10, transforming growth factor-β2) and proangiogenic (bFGF, VEGF) cytokines are increased in metastatic melanoma. Inverse plasma levels between IL-10 and VEGF in patients with metastatic melanoma are shown in vivo for the first time, the significance of which must be further investigated.