MAPK3 and melanoma: Whereas the melanoma factors causing this signaling cascade in keratinocytes are not yet identified, Burks et al. showed that keratinocytes treated with melanoma-conditioned media secrete CXCL1, an inflammatory chemokine whose secretion relies on the activation of the ERK1/2 pathway, and which promotes melanoma cell migration via the CXCR2 receptor in melanoma cells.