Fig. 1

Optimization of exogenous estrogen supplementation methods to promote HCI-013 tumor growth in experimental mice. a Experimental timeline. 8 weeks old female NSG-SGM3 or NSG mice were inoculated with HCI-013 tumor fragments into the MFP (n = 5). On the same day, mice were implanted with 0.4 mg E2 pellets, while 4 weeks post tumor implantation, mice received E2 supplemented acidified drinking water until the end of the experiment. This reflects our standard exogenous estrogen supplementation for ER+ PDX lines [15]. b Tumor growth was monitored until mice were harvested 8 weeks post tumor implantation (n = 5). HCI-013 PDX tumors have previously been reported to have heterogeneous growth (DeRose et al. 2011), which we also observed here. c Experimental timeline. 8 weeks old female NSG-SGM3 mice were implanted with HCI-013 tumor fragments into the MFP (n = 5). On the same day, mice were either implanted with 0.2 mg E2 pellets, which represents half of the pellet size of our standard protocol (upper timeline), or received E2 supplemented acidified drinking water until the end of the experiment (lower timeline). d Tumor growth was monitored until mice were harvested 10 weeks post tumor implantation (n = 5)