MAPK3 and neoplasm: To investigate whether expression of P53R172H and KRASG12D is capable of inducing skin cancer and whether tumor growth in skin can be monitored via in vivo imaging of the co-expressed reporters, 2PLEASE mice were crossed with R26-Cre-ERT2 mice and the double transgenic offspring (2PLEASE; R26-Cre-ERT2) were treated topically with tamoxifen on the dorsal skin following depilation.