GSR and neoplasm: Indeed, we detected increased levels of malondialdehyde (a product of peroxidation of polyunsaturated fatty acids) and increased activity of enzymes that counter oxidative stress (i.e., catalase, glucose-6-phosphate dehydrogenase and glutathione reductase) in tumours treated with CBIs and, to a higher extent, with CBIs plus fasting (Supplementary Fig. 8b).