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Cancer

Intro

Sometimes, cells in an organism go rogue; they don’t listen to signals from other cells, and start reproducing and form a tumor; they hog the nutrient supply coming to that region. As they reproduce, they make inexact copies of themselves, and they fight with each other for the limited nutrient supply: the ‘survival of the fittest’ game is seen within the tumor, and repeatedly one type of cell comes to dominate others.

Often, after many generations some of these cells evolve the ability to swim in blood vessels and deposit themselves in other parts of the organism (or even in other organisms in rare cases such as the Tasmanian devil mouth tumor epidemic). THe cancer is then said to be malignant.