KRAS and cancer: Since CSC expansion of CRC tumoroids is hitherto unknown, we cultured three human CRC cells lines, HT29 (p53 mutant, K-RAS wild type, microsatellite stable), HCT116 (p53 wild-type, K-RAS mutant, microsatellite instable) and KM12 (p53 mutant, K-RAS wild type, microsatellite instable)21, and CT-26 murine cancer cells (p53 wild-type, K-RAS mutant, microsatellite stable)22 on 3D scaffold for 6 days and examined tumoroids for stemness markers by qPCR and flow cytometry.