RDNCancer causes loss of muscle (cachexia) through the release of a protein, Activin-A, that causes leakiness and loss of blood vessels, even those far from the tumor.
Original paper: https://www.nature.com/articles/s43018-025-00975-6
Muscle weakness in cancer survivors may be caused by treatable weakness in blood vessels – new research
Many cancer survivors struggle with muscle weakness, which can be so profound that they may have difficulties walking up a couple of flights of stairs or going shopping for groceries on their own.
WikiPathways