To explore the FGF2 expression pattern in estrogen receptor positive (ER + ) and aggressive triple negative breast cancer (TNBC) subtypes, we performed immunohistochemical staining for FGF2 in 38 ER+ and 18 TNBC primary tumor samples (Fig. 5A, Supplementary Fig. 7). The gene discussed is ESR1; the disease is triple-negative breast carcinoma.