1. Metastasis

2. 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

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

4. 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

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

6. 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

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

8. 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

9. 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

10. 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