Why cancer patients waste away

A tumor-produced protein prevents cells from consuming sugar, two fly studies find


SHRIVELED  Tumors implanted in adult female fruit flies cause healthy ovaries (one shown, left) to waste away. The wasting (right) is caused by a protein secreted by cancer cells. The bar shown represents 500 micrometers.

D. Bilder and A. Figueroa-Clarevega/Univ. of California, Berkeley

A protein released by tumors is what causes cancer patients to waste away, studies of fruit flies suggest.

Fat and other tissues all over the body wither in people with cancer, but the reason for the wasting, also called cachexia, was not understood. Cancer cells secrete a protein called IMPL2, researchers from Harvard Medical School and the University of California, Berkeley independently report in the April 6 Developmental Cell. Both teams came to the conclusion that the protein is responsible for wasting after giving fruit flies cancer.

IMPL2 prevents healthy cells from responding to insulin, a hormone that stimulates cells to import sugar and burn it for energy. When levels of IMPL2 rise, fat, muscle and other tissues can no longer consume sugar and begin to waste away. Lowering IMPL2 levels reduces the amount of wasting, both groups found.

Other factors may also be involved in wasting, the researchers say.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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