MPV17 and neoplasm: The casper (roy; nacre) zebrafish (White et al., 2008), first developed in 2008 as a tool for improved tumor engraftment visualization, is a combinatorial pigmentation mutant derived from the melanocyte mutant nacre (mitfa–/–; Lister et al., 1999) and the iridophore mutant roy orbison (mpv17–/–; Ren et al., 2002; D’Agati et al., 2017).