Metastasis

Vocab Metastasis-spread of cancer from one part of the body to another. metastatic tumor or metastasis- tumor formed from cells that have spread metastases-multiple metastatic tumors

Metastasis Cancer cells breach basement membrane and invade stroma Find way to blood or lymphatic vessel Intravasation- invasion into blood vessels Enter venous system

Metastasis Blood is hostile environment Success enhanced if cancer cells attract blood platelets to “escort” them. Anoikis- apoptosis triggered when cell is not bound on solid substrate

Where do they go? Venous system is pumped through heart, then enters lungs Small capillaries in lungs, deformed cells may not fit Metastasis!

Where do they go? Escape the lungs enter arterial system free to go wherever Extravasation- escape from the blood vessels and penetrate into surrounding tissue

Where do they like to go? Colonization- cells form tumor mass in new tissue New environment, may die out, or remain as micrometastases

Where do they like to go? Cellular changes govern where tumor cells will be able to survive… become HIGHLY SPECIALIZED for that organ Survival of the fittest

Where do they like to go? 75% of thyroid cancers spread to the lymph nodes only 3% form distant metastases Colon cancers spread to the liver Duodenal tumors spread to lymph nodes rarely liver

Where do they like to go? “Seed and Soil Hypothesis” Stephen Paget The ability of a cancer cell to successfully metastasize to another location depends on the environment of the new tissue