Is colorectal cancer caused by a genetic defect leading to polyps?

Yes and no: All benign and malignant tumors result from accumulated genetic mutations. There are a few hereditary illnesses in which a child inherits a first mutation in the series that leads to colon cancer. However, most people with colon cancer began life with a genome free of cancer-causing mutations. Benign polyps may or may not acquire additional mutations and turn cancerous.