KRAS and colorectal carcinoma: Among our three CRC cell lines forming TNTs, LOVO cells harbor MSI and G13D KRAS and are derived from a metastatic lesion; this cell line formed significantly more TNTs than HCT-116 and HCT-8; HCT-116 is characterized by MSI and G13D KRAS, but derived from a primary tumor, and HCT-8 is characterized by only MSI.