TGFB1 and intestinal neoplasm: Previous studies have reported that intra-splenic transplantation of organoids from mouse intestinal tumors, with combined Apc, KrasG12D, Trp53, and TGF-β signaling mutations, is the most efficient means of generating metastases (Tauriello et al., 2018, Sakai et al., 2018) (Figure 7A).