Tasmanian Devils' Disease Unveiled: Deadly Cancer Turns off Genes, Evades Immune System

Article excerpt

A contagious cancer devastating Tasmanian devils makes itself invisible to the animals' immune systems, which might otherwise fight it off, a new study shows.

Devil facial tumor disease shuts down production of proteins that normally decorate the surfaces of cells, telling the body whether a cell belongs to it or not. As a result, a Tasmanian devil's immune system doesn't recognize cancer cells from another devil as invaders, Hannah Siddle, a geneticist at the University of Cambridge in England, and collaborators report in the March 26 Proceedings of the National Academy of Sciences.

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The finding could lead to a way to stop the deadly disease. "It's really the first hope that there could be a vaccine or immune therapy," says Elizabeth Murchison of the Wellcome Trust Sanger Institute and the University of Cambridge. Murchison discovered in 2009 that the tumor originated in cells of a single devil. Since that initial case, which probably occurred in the late 1980s or early 1990s, the disease has spread across eastern and central Tasmania, killing every devil it infects.

Siddle and her colleagues discovered that devil facial tumor cells turn off genes that the immune system uses to distinguish between cells from its own body and foreign cells. Without the proteins made by these major histo-compatibility complex, or MHC, genes, the tumor cell can conceal its true identity as a cancer cell and tissue from another animal. …