Definition of Metastasis
Metastasis: 1. The process by which cancer spreads from the place at which it first arose as a primary tumor to distant locations in the body.
Metastasis depends on the cancer cells acquiring two separate abilities -- increased motility and invasiveness. Cells that metastasize are basically of the same kind as those in the original tumor. If a cancer arises in the lung and metastasizes to the liver, the cancer cells in the liver are lung cancer cells. However, the cells have acquired increased motility and the ability to invade another organ.
The ancient Greeks used the word metastasis to mean "removal from one place to another." The plural of "metastasis" is "metastases."
Last Editorial Review: 8/28/2013
Back to MedTerms online medical dictionary A-Z List
Need help identifying pills and medications?