The CHRONOS study has demonstrated that patients with metastatic colorectal cancer [17], who have progressed due to RAS/RAF mutations after previous response to anti-EGFR treatment and who lacked detectable BRAF or RAS mutations in ctDNA after progression to the last anti-EGFR-free regimen, could be successfully re-challenged with anti-EGFR treatment. This evidence concerns the gene BRAF and metastatic colorectal cancer.