The Tumor Microenvironment in Cutaneous Melanoma: Friend or Foe

Malignant melanoma is one of the most aggressive and lethal cancers. Even a primary tumor of 1 mm in thickness can metastasize and kill the patient. However, without the interactions with a supporting microenvironment, the tumor cannot grow and thrive. Most of the time, the microenvironment imposes an inhibitory effect on melanoma growth, and the vast majority of mutated neoplastic cells occurring during life will be destroyed. But how is the tumor microenvironment (TME) sometimes co-opted to support tumor growth? Does it not recognize the tumor lesion as a potential threat? Does the TME perceive the tumor as “a wound that needs to heal”? This chapter will describe some important players in the melanoma microenvironment. In addition to the biology of the melanocyte, the different roles played by keratinocytes, fibroblasts, endothelial cells, and immune cells will be discussed.