With respect to primary tumor growth, PAR2−/− mice subcutaneously inoculated with B16 melanoma cells exhibited larger primary tumors, while orthotopic xenografts of the human PDAC cell line Panc1 expressing a kinase-active mutant of the TGF-β type I receptor ALK5 in scid/bg mice presented with smaller primary tumors. This evidence concerns the gene TGFBR1 and neoplasm.