We found that TBX2 was variably expressed across the different molecular subtypes of breast cancer [58] (Figure S2A), largely independent of estrogen receptor (ER) status and tumor grade (Figure S2B, S2C), with the highest expression levels among the rare, aggressive ‘claudin-low’ subtype of breast cancer and lowest in basal tumors (Figure S2A). Here, ESR1 is linked to neoplasm.