TFF2 and melanoma: Notably, Setlow and colleagues first used the hybrid model shown in Figure 4(D) (called Sp-helleri to designate the Sp-Mdl allele backcrossed into the X. helleri genetic background) to study UVB induction of melanoma, demonstrating several-fold increased induction of melanoma at 4–6 months after irradiation of 5-day-old fry (Setlow et al., 1989).