After validating the specificity of the anti-FOXM1 antibody using tissue from tumors with FOXM1 silencing (Supplemental Figure 9E), we used it to show that nuclear FOXM1 protein expression correlated positively with SFK activity [p-SFK (Y416)] in ERα+Ki67hi luminal B–like tumors (23, 24) from an independent cohort of 160 patients with breast cancer (Figure 10A and Supplemental Figure 11A). Here, ESR1 is linked to breast carcinoma.