EGFR and metastatic colorectal cancer: When AREG was analyzed separately as a dichotomous variable, the CALGB 80203 and PICCOLO trials showed that AREG mRNA expression and AREG IHC were neither prognostic markers nor predictive markers of benefit from EGFR-targeted therapy in RAS wt metastatic colorectal cancer (Table 5; Fig. 7a, b).