To model integrin β1 (hereafter referred to as ITGB1) phosphorylation during invasive breast cancer progression, we knocked down the ITGB1 mRNA in MDA-MB-231 (MM231) breast cancer cells using a lentiviral short-hairpin RNA (shRNA) (MM231 shβ1 cells; Extended Data Fig. 1a). The gene discussed is ITGB1; the disease is breast cancer.