However, given the recent focus on how k-ras mutations affect clinical outcome in metastatic colorectal cancer and anti-EGFR therapy with cetuximab [39–41, 57], evaluation of patients for mutations in k-ras is rapidly becoming part of routine practice in clinical oncology and had so far mostly relied on formalin-fixed paraffin-embedded (FFPE) tumor tissue. This evidence concerns the gene KRAS and metastatic colorectal cancer.