Fig. 2

In vivo drug response to BYL719 or fulvestrant alone and combined in the HBCx-34 PDX model. a Effect of the different treatments on HBCx-34 tumor growth. Each treatment included 10 mice; the y-axis indicates the mean of RTV + SD. b Waterfall plot representing the percent of change in tumor volume from baseline in individual HBCx-34 xenografts in the different treatment groups. c PLA was performed on treated tumors embedded in paraffin to study the interactions between ERα and PI3K. Quantification was performed by counting the number of signals per cell in five independent zones of the section (n > 500 cells counted/tumor). Significance (P value) between treatments was determined using the Student t test. ns, non-significant; *P < 0.05; **P < 0.01. d Expression of estrogen-regulated genes (ERG) analyzed by RT-QPCR in PDX tumor samples (N=4). e IHC staining was performed on formalin-fixed paraffin-embedded PDX tumors using anti-ERα and anti-P-S6 riboprotein (S235/6) antibodies. Quantification of highly, medium, and negative cells was performed as described in the “Materials and methods” section. Significance (P value) between treatments and controls were performed using the t test. ns:not significant