Colorectal(直腸)cancer is the third-leading cause of cancer death in the US. Family history, smoking and diet are all linked with colorectal cancer, and it is estimated that nearly 1 percent of colorectal cancer cases are linked to one hereditary genetic mutation. People with this mutation have a greater than 2 in 3 risk of developing colon cancer by age 80, compared to about 1 in 24 for the general population. After an extensive study of thousands of members of a large American family living in New York and Utah, researchers were able to trace the cancer-causing mutation to a single British couple that arrived in New England in 1630.