RAS and BRAF mutations in cell-free DNA are predictive for outcome of cetuximab monotherapy in patients with tissue-tested RAS wild-type advanced colorectal cancer

In metastatic colorectal cancer, RAS and BRAF mutations cause resistance to anti-EGFR therapies, such as cetuximab. Heterogeneity in RAS and BRAF mutations might explain nonresponse in a subset of patients receiving cetuximab. Analyzing mutations in plasma-derived circulating tumor DNA (ctDNA) could provide a more comprehensive overview of the mutational landscape as compared to analyses of primary and/or metastatic tumor tissue. Therefore