Kaplan-Meier plots comparing progression free survival (PFS) in two KRAS wild-type, advanced CRC patient cohorts treated with cetuximab. For both cohorts, we dichotomize on the median of the estimated RIS. [A] KRAS wild-type patients (n=37) from the Khambata-Ford data set, separated by RIS (p=.016, log-rank test, HR=2.3, 1.2-4.9 95%CI). [B] KRAS wild-type patient (n=85) from blinded validation set. PFS is significantly lower in the high RIS patients compared to low RIS patient (p=.007 log-rank test, HR =2.0 CI95% [1.2-3.3]).