Intraperitoneal spread may also occur in the peritoneal cavity. However, this is not specific for colon carcinoma. CEA may also be present in the serum in patients with gastric cancer or breast cancer. Some non-neoplastic conditions may also be associated with CEA in the serum. Ulceration causes bleeding, and this is detected as blood in the stools.
Local invasion is highly related to distant spread.
To degrade the ECM, they produce proteolytic enzymes such as collagenase type IV and plasminogen activator. Ras is the most commonly mutated protooncogene in human cancer. When cells experience DNA damage, the normal p53 gene causes cell cycle arrest in G1, providing time for repair of DNA damage. Ras in normal cells is a signal-transduction molecule. The latter is the active form of ras, and it sends growth-promoting signals to the nucleus.