My sister has sarcoma cancer which has attached to the heart muscles so surgery was not successful. Right now, she was diagnosed in july, 2014, right now she has been sleeping a lot, since last Friday the 2nd of january.her breathing is deeper so her husband increased her oxegen, she won t eat, mouns while sleeping, is this a stage of the cancer ? Her daughter thinks she has a cold?

Summarized question: What causes sarcoma cancer?