Angiogenesis, vasculogenic mimicry and vascular invasion in cutaneous malignant melanoma - implications for therapeutic strategies and targeted therapies.

Angiogenesis, defined as new vessel growth from a pre-existing vessel, has been shown to be crucial for tumor survival and growth in several lineage-unrelated malignancies including melanoma. The concept of vasculogenic mimicry, a highly patterned microcirculation independent of angiogenesis, has also been described in melanoma. The prognostic value of vascular invasion, characterized by the presence of tumor cells within vascular channels, in melanoma remains controversial as in the current American Joint Committee on Cancer-staging system for melanoma vascular invasion is not included for microscopic staging purposes. This review summarizes contemporary understanding of these three processes i.e. angiogenesis, vasculogenic mimicry, and vascular invasion in an effort to uncover putative targets as therapeutic strategies in melanoma.