In Vivo human melanoma cytokine production: Inverse correlation of GM-CSF production with tumor depth

Abstract: Melanomas produce multiple cytokines which may influence their growth in vivo . Experimental evidence suggests that granulocyte macrophage-colony stimulating factor (GM-CSF) can induce a potent anti-melanoma response, whereas interleukin-8 (IL-8) may act as a growth factor in human melanoma. Little is currently known regarding the production of these cytokines by human melanoma in vivo . In this study we tested the hypothesis that endogenous production of GM-CSF and IL-8 can be correlated with the depth of human malignant melanoma surgical specimens. We examined 45 melanocytic human tissue samples consisting of 27 primary cutaneous melanomas, 9 metastatic melanomas, and 9 dysplastic nevi for in vivo GM-CSF and IL-8 production using immunohistochemistry. The majority of thin melanomas (≤0.76 mm) stained highly positive for GM-CSF with little or no staining for IL-8 whereas the medium (≤0.76 –≤4.0 mm) and thick (>4.0 mm) melanoma specimens showed little or no staining for GM-CSF and significant amounts of IL-8 staining. Metastatic melanoma as well as dysplastic nevi specimens had little or no GM-CSF and IL-8 staining. These results support the hypothesis that endogenous melanoma cytokines such as GM-CSF and IL-8 with opposing effects on tumor progression play an important role in melanoma growth and regulation.