RHOA and melanoma: Other recent applications of intravital FRET investigating, for example, RhoA (Nobis et al., 2017), intricate Erk signalling propagation events from in the skin (Hiratsuka et al., 2015) or cancer stemness (Kumagai et al., 2015), PKA in vascular permeability (Yamauchi et al., 2016) and stromal targeting in melanoma (Hirata et al., 2015) could benefit from this approach.