For the 500,000 new cases of colorectal cancer in the world each year, identification of patients with a worse prognosis and those who are more likely to respond to treatment is a challenge. There is an increasing body of evidence correlating genetic mutations with outcome in tumours derived from human colorectal cancer cohorts. K-ras, but not p53 or APC, mutations appear to be associated with poorer overall survival in colorectal cancer patients.