The changes that take place in an ADENOMA, a benign (noncancerous) tumor, as it transforms into an ADENOCARCINOMA, a malignant (cancerous) tumor. The transition to cancer can occur with any adenoma though is most common with adenomas of the colon (intestinal polyps, also called adenomatous polyps). Only a small percentage of adenomas become cancerous.
The sequence of events that transform an adenoma to an adenocarcinoma begins with multiple mutations in the genes that regulate cell division and APOPTOSIS (planned cell death). Over a series of cell divisions the mutations become increasingly prevalent among the cells, resulting in DYSPLASIA and ultimately cancer. Because of the risk for an adenoma to become adenocarcinoma, doctors often surgically remove adenomas when feasible.