IRS1 and breast cancer: There are two publications from the same research team that demonstrated, through RNA sequencing (RNAseq) analysis in the pectoralis major muscle, a greater expression of genes related to ubiquitin-mediated proteolysis, NADH: ubiquinone oxidoreductase core subunit S8 (Ndufs8), and a decrease in the expression of genes related to insulin receptor substrate 1 (IRS1) protein synthesis in women with breast cancer undergoing chemotherapy [34,35].