For those with PRLR-high tumors and with an early BC event, FOXA1 (no RT dES = 1.68; RT dES = 1.87, Padj < 0.05—Figure 4H) and SPDEF (no RT dES = 1.65; RT dES = 1.83, Padj < 0.05—Figure 4G), regulons were found to be activated regardless of radiotherapy status. Here, SPDEF is linked to breast cancer.