Colon cancer development starts with the formation of benign tumors called adenomas. It is estimated that between 30% and 50% of people over 50 will develop one of these tumors. These adenomas or polyps are the pre-cancerous lesions that, once they accumulate further genetic mutations over many years, can progress to colon cancer. A team has discovered that the colon has a safety mechanism to restrict the formation and growth of adenomas.