EGFR and cancer: An example of the cancer temporal heterogeneity [268, 269] is given by Parseghian et al. [270] study in which in the mCRC RAS wild type patients, after discontinuation of anti-EGFR antibodies, the ctDNA liquid biopsy predicts the decline of KRAS mutant-clones and provides evidence for re-challenge therapy with the anti-EGFR antibodies.