GSTA4 and skin neoplasm: The skin tumor promotion susceptibility locus, Psl1, was previously mapped to a 59.1-Mb region of mouse chr 9 (Angel et al. 1997, 2001, 2010; Angel and Digiovanni 1999) and the glutathione S-transferase gene, Gsta4, was shown to underlie at least some of the effect of this locus on skin tumor promotion susceptibility in mice (Abel et al. 2010).