AXL and melanoma: Remarkably however, the absence of MITF marks a AXL+/WNT5A+ population of melanoma cells – previously identified as the ‘Hoek's invasive signature cohort’ (Hoek et al., 2006) – that is unresponsive to MAPK pathway inhibitors (Anastas et al., 2014; Konieczkowski et al., 2014; Muller et al., 2014; O'connell et al., 2013).