The TKO and Trp53; Ptpn12 DKO tumors were classified as high-grade angiosarcoma due to the prominent nuclear pleomorphism, atypical mitosis and solid tumor areas observed while tumors from the Pten; Ptpn12 DKO mice were classified as low-grade with minimal atypia, lack of atypical mitosis and anastomosing morphology. This evidence concerns the gene PTPN12 and angiosarcoma.