In a retrospective study examining 146 patients with locally advanced rectal cancer, Bengala et al. demonstrated that patients with mutated KRAS had a decreased rate of complete response to concomitant chemoradiation with continuous infusion of 5-FU with or without oxaliplatin or capecitabine compared to wild-type patients (7.4% vs. 19.2%) [59]. The gene discussed is KRAS; the disease is rectal cancer.