KRAS and colorectal carcinoma: In metastatic CRC, there were studies showed that KRAS MT patients had worse progression-free survival (PFS) (Modest et al., 2016; Souglakos et al., 2009) or overall survival (OS) (Modest et al., 2016) than KRAS WT patients, while other study found there was no association between KRAS mutation status and PFS or OS of CRC patients (Kim et al., 2016).