Human intestinal PDOs and PDTOs, genetically modified by means of CRISPR-Cas9, have been used to study the role of genes and factors in CRC progression [84] and that of genes involved in the resistance to TGF-β-mediated growth restriction [85], as well as to identify tumor suppressor genes in vivo [86]. The gene discussed is TGFB1; the disease is colorectal carcinoma.