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<\/div>A cancer cell and two immune cells<\/p>\n
STEVE GSCHMEISSNER\/SCIENCE PHOTO LIBRARY\/Alamy<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
Cancer is a disease, or group of diseases, in which some cells proliferate uncontrollably and can spread to other parts of the body. But that description doesn\u2019t reflect how our conception of cancer has changed, says Kenneth Pienta<\/a> at Johns Hopkins University in Maryland. \u201cPeople used to view cancer as sort of bad luck: the cancer would just change over time and we didn\u2019t really understand why, or how, or what was driving those changes.\u201d<\/p>\n In the past few years, however, Pienta and others have come to see cancers as akin to organisms themselves, existing in complex ecosystems alongside other cancer cells and host immune cells. Cancer cells compete for access to nutrients, and only the fittest survive. \u201cCancer evolves in response to changes in its environment,\u201d says Pienta. \u201cIf it didn\u2019t, it would die.\u201d<\/p>\n Ultimately, this is the reason why cancer kills so many people. Cancer cells divide rapidly, so random mutations occur often and any that confer an advantage are quickly selected for. \u201cThey\u2019re evolving to become the best cancer cell they can become and that typically is bad news for the patient,\u201d says Robert Gatenby,<\/a> co-director of the Cancer Biology and Evolution Program at the Moffitt Cancer Center in Florida.<\/p>\n What\u2019s more, the hardiest cells are better at getting into the bloodstream and spreading to other parts of the body, a process known as metastasis. \u201cWe have got good drugs and initial therapies for most types of cancers,\u201d says Gatenby. \u201cBut in the metastatic\u2026<\/p>\n<\/p><\/div>\n