FZD5 and neoplasm: WNT2 can activate both canonical and non-canonical WNT signalling (Mazzotta et al., 2016; Najdi et al., 2012), while FZD5 and FZD9, both of which are expressed in the high-amplified tumours, activate different branches of the pathway (FZD5 the canonical pathway and FZD9 the non-canonical pathway) (Wang et al., 2016).