PTPRC and hyperplastic polyp: One proximal adenocarcinoma (B241, Mlh1+/+ WD) and five adenomas/hyperplastic polyps (adenomas: B219, Mlh1+/+ WD; B220, B236, Mlh1+/- WD and hyperplastic polyps: B215 Mlh1+/- WD; B244, Mlh1+/- AIN) were observed in the 32 mice at tp1 and none of them occurred in the control mouse group.