Muscle loss in cancer is a cause of death

(written by Lawrence Krubner, however indented passages are often quotes)

I did not know that loss of muscle, caused by cancer, was a cause of death separate from the cancer itself:

Muscle wasting — called cachexia — is thought to account for about 30% of deaths in patients with cancer, but how exactly cachexia is spurred by cancer — or indeed exactly how it leads to a patient’s decline — isn’t known. It is thought that several molecular pathways work in tandem, “activating an axis of evil to control muscle mass in a negative way”, says H. Q. Han, lead author of the study and scientific director of the metabolic disorders division at Amgen, a biotechnology company in Thousand Oaks, California.

Han and his group wanted to find the dominant pathway responsible for cancer cachexia, and then design a way to block it in order to treat patients. Several studies have shown that blocking the myostatin pathway can promote muscle growth, says Han, and some have shown that a molecule closely related to myostatin, called activin A, becomes more abundant in patients with some cancers.

“We examined a large random collection of cancer cell lines in vitro, and found that one-third of them secreted large amounts of activin A,” says Han. “This led us to believe that activin A must have some systemic function when overproduced in a cancer setting.”