RGS4 and melanoma: Regulator of G protein signalling 4 (RGS4) has been found to inhibit human melanoma (in the same cell line tested in this study, M14), and RGS4-silenced neuroblastoma exhibits decreased SLC7A11 expression [41], suggesting a possible role of RGS4-mediated increase in SLC7A11 in the course of melanoma inhibition.