ACVRL1 and neoplasm: Interestingly, 12-week old compound RIP1-TAg2; Acvrl1+/−Eng+/− mice presented with a significantly reduced overall tumor burden by 57% and 39%, compared to RIP1-TAg2; Acvrl1+/+Eng+/+ mice or RIP1-TAg2; Acvrl1+/−Eng+/+ mice, respectively (Figure 3A).