Evidence from lung cancer (Engelman et al, 2007), pancreatic cancer (Frolov et al, 2007), melanoma (Reschke et al, 2008) and head and neck cancer (Erjala et al, 2006) suggest that ErbB3-dependent signalling mechanisms are important for not only disease progression, but also resistance to EGFR-targeted therapies. This evidence concerns the gene EGFR and melanoma.