Figure 1.

Schematic representation of tumor–stroma cross-talk. In melanoma, tumor cells share their microenvironment with MAFs, immune cells and blood vessels. Resident fibroblasts might oppose an early anti-tumor activity or facilitate tumor development, whereas, during disease progression, activated MAFs gradually acquire a marked pro-tumorigenic phenotype. An intense bi-directional exchange of soluble factors between melanoma and surrounding cells significantly modifies in MAFs several intracellular signaling pathways including oncogenic pathways. Extracellular matrix supports tumor architecture and influences various signal transduction pathways in both tumor and associated cells.