Fig. 3

a Quantile-quantile plot of small RNA p values for association with letrozole/bevacizumab response. The observed p values from the association of small RNA expression values with letrozole/bevacizumab response (see the “Methods” section) are plotted against the null (uniform) distribution. Small RNAs selected by LASSO regression for an optimal classifier model (see the “Methods” section) are marked by black dots and labeled. b Classifier model performance on three cohorts. Classifier values calculated from qPCR data for each patient tumor sample (x-axis) across three cohorts are plotted on the y-axis (see the “Methods” section). Bar color indicates responder status. The dotted line indicates the common threshold used to calculate model accuracy. The “discovery cohort” is the cohort of patients who received letrozole/bevacizumab in the present study. The “validation cohort” is the cohort of patients who received the same treatment in a separate independent clinical trial [15]. The “letrozole cohort” consists of patients who received letrozole in the present study. The model was trained on sequencing data from the discovery cohort