Acquired KRAS mutations during progression of colorectal cancer metastases: possible implications for therapy and prognosis

Documentation of a wild-type (wt) KRAS gene in tumor has become mandatory for the prescription of anti-EGFR monoclonal antibodies in patients with colorectal cancer (CRC). Acquired KRAS mutations have seldom been reported in metastases from wt KRAS primary CRC. We report the first case of multiple KRAS mutations acquired during the metastatic phase of CRC, and retrospectively reviewed all patients with CRC, in whom KRAS was analyzed in at least two tumor samples from distinct lesions.