EGFR and metastatic colorectal cancer: Since LCS6 is a functional SNP in the Let-7-binding site of KRAS that impacts KRAS expression, and KRAS overexpression has been accepted in clinical practice as a negative predictive biomarker for patients treated with anti-EGFR therapy 39, we performed a subgroup analysis on metastatic colorectal cancer patients treated with anti-EGFR therapies (four studies with an aggregate of 643 patients).