If cancer metastasizes or spreads from its original site, certain cancers have a preference for certain organs. This is known as "organ tropism." This image depicts cancer cells (purple) metastasizing from the original site in the epithelium. These cells are traveling through the blood and lodging in the lungs and bone. Testicular cancers typically metastasize to lungs, brain, and bone.
Cancer cells usually spread through blood or lymph vessels (see cancer metastases, workbook). Several factors may encourage certain types of cancer cells to metastasize to specific organs. These include:
- The organ may produce growth factors making it easier for cancer cells to colonize in that location
- Hormones may encourage the growth of cancerous cells in a specific location
- The tissue may have specific protein receptors for the cancerous cells encouraging growth in this location
- The route through the blood vessels or lymphatic system may pass through the targeted organ