Overall, 27 somatic mutations in ALK5 were identified among the 907 endometrial tumors queried (S1 Fig); 40.7% (11 of 27) of mutations, including the recurrent S241L-, R255C-, and R487G-ALK5 mutations, localized within the protein kinase domain, and 14.8% (4 of 27) were in the Activin types I and II receptor domain. This evidence concerns the gene TGFBR1 and endometrium neoplasm.