SMAD4 and neoplasm: CRISPR/Cas9 technology has also been adopted to establish organoid tumor models.81,82 For instance, organoid colon cancer models were constructed in vitro with CRISPR technology by introducing mutations of tumor suppressor genes (APC, TP53, SMAD4, etc.)and gene modification of oncogenes (KRAS, PI3K, etc.).83 Moreover, guided by colonoscopy, through mucosal injection, Roper et al.84 established CRISPR engineered mouse tumor organoids by delivering viral vectors carrying CRISPR/Cas9 components to the distal colon of mice.