To further characterize an apparent antiestrogenic effect of FASN blockade in ER+/HER2+ breast carcinomas, mice bearing MCF-7/HER2-18 tumors were randomized in a second set of independent experiments to receive E2 supplementation, estrogen deprivation either alone or with the SERM fulvestrant (FVT; ICI 182,780), or fulvestrant with continued estrogen supplementation in the absence or presence of C75 (Figure 5). This evidence concerns the gene ESR1 and breast carcinoma.