Metastasis

Definition

Metastasis is the process by which cancer cells spread from the original (primary) tumor to distant sites in the body, forming secondary tumors. This process is a key feature of cancer progression, as it enables cancer to invade tissues and organs beyond the initial site, making treatment more complex and challenging. Metastasis involves several steps, including local invasion, entry into the bloodstream or lymphatic system, survival in circulation, and colonization at new sites.

5 Must Know Facts For Your Next Test

1. Metastasis is responsible for approximately 90% of cancer-related deaths, as it often indicates a more advanced stage of disease.
2. The spread of cancer can occur through various routes, including blood vessels, lymphatic vessels, or direct invasion of neighboring tissues.
3. Certain cancers are more prone to metastasizing than others; for example, breast, lung, and prostate cancers are known for their high metastatic potential.
4. The ability of cancer cells to metastasize is influenced by their genetic makeup and the microenvironment they encounter at distant sites.
5. Prevention of metastasis is a significant focus in cancer research, with efforts aimed at targeting the specific mechanisms that allow cancer cells to migrate and establish secondary tumors.

Review Questions

• What are the critical steps involved in the process of metastasis and how do they contribute to cancer progression?
  • The critical steps in metastasis include local invasion of surrounding tissues, entry into blood or lymphatic systems, survival during circulation, and colonization at distant sites. Each step is crucial as it enables cancer cells to escape the primary tumor's confines and establish secondary tumors elsewhere in the body. This progression leads to a more aggressive form of cancer that is harder to treat and often results in poorer patient outcomes.
• How does angiogenesis support the metastatic process in cancer development?
  • Angiogenesis plays a vital role in supporting metastasis by providing newly formed blood vessels that supply nutrients and oxygen to tumors. As cancer cells spread, they rely on these blood vessels not only for sustenance but also as pathways for entering circulation. Without angiogenesis, tumors would struggle to grow beyond a certain size or survive after metastasizing due to insufficient resources.
• Evaluate the impact of genetic factors on a cancer cell's ability to metastasize and discuss potential therapeutic strategies that target these mechanisms.
  • Genetic factors significantly influence a cancer cell's ability to metastasize by affecting its invasive properties and interactions with the microenvironment. Mutations in specific genes can enhance motility, promote angiogenesis, or aid survival in circulation. Therapeutic strategies that target these genetic alterations aim to inhibit pathways involved in cell migration and invasion. For example, drugs that block signaling pathways responsible for tumor cell movement could reduce metastasis and improve treatment outcomes for patients with aggressive cancers.

Related terms

tumor: An abnormal mass of tissue that arises from uncontrolled cell division and can be benign (non-cancerous) or malignant (cancerous).

angiogenesis:

The formation of new blood vessels from existing ones, which tumors exploit to obtain nutrients and oxygen necessary for their growth and spread.

extravasation: The process by which cancer cells exit the bloodstream or lymphatic system and invade surrounding tissues, facilitating metastasis.