DCD and neoplasm: This seems to happen mainly as a result of enhanced degradation of sulphur amino acids to sulphuric acid in skeletal muscle [132], very likely as a result either of cytokines (such as TNF-alpha) [90,122], proteolysis-inducing factor (PIF) coming from tumour cells [134], or other signal substances enhancing the rate of reactive oxygen species (ROS) production in the muscle cells.