Amelanotic changes in B 16 melanoma after transplantation to 'Yellow' Ay/a mice.

B 16 mouse melanoma maintained on nonagouti a/a mice (C 57 Bl 6j subline) was transplanted to 'Yellow' Ay/a mutants. B 16 melanoma has now been maintained for 1 year on the 'Yellow' strain. A microscopic and ultrastructural study of transplanted tumors is described. Several enzymatic activities including tyrosinases are investigated. A marked depigmentation of the B 16 melanoma is noted after its transplantation to the 'Yellow' strain, and melanogenic characteristics of the tumor are modified.