C-FOS is known to be stabilized by phosphorylation at serines 362 and 374 upon ERK1/2 activation downstream to the MAPK pathway, which is constitutively activated in most melanomas.22–24 Phospho-FOS (PS374-FOS) and c-FOS evaluation by western blot confirmed their variable levels, thus supporting the complex relationship between miR-221&222 expression levels and c-FOS phosphorylation and stability (Fig. 3d). The gene discussed is FOS; the disease is melanoma.