Current position of TNF-α in melanomagenesis.

Melanoma is one of the most heterogeneous and immunogenic forms of cancer. Both tumor and stroma cells synthesize many cytokines involved in rapid development and metastasis. One of these cytokines from the tumor milieu is tumor necrosis factor-alpha (TNF-α), which seems to have an intricate role in melanomagenesis. Initially, it was found that TNF-α can induce apoptosis of tumor cells through both extrinsic and intrinsic pathways, in contrast with later studies that revealed its protumoral activity. TNF-α is involved in inflammation, inducing the secretion of survival molecules like antiapoptotic proteins, proangiogenetic factors and metastasis markers. Although there are many therapeutic strategies against melanoma, the prognosis of advanced stages remains poor, due to several tumor resistance mechanisms. TNF seems to be a negative prognostic factor in melanoma surgery and correlates with chemotherapy resistance. However, high intratumoral levels of TNF-α might be beneficial for immunotherapy. Researchers may redirect their studies in the future by double activating of the proinflammatory molecule TNF-α and the immune cells in order to obtain an antitumoral response in metastatic melanoma.