Summary: Therapies targeting epidermal growth factor receptor (EGFR) have variable and unpredictable responses in breast cancer. Screening triple-negative breast cancer (TNBC) patient-derived xenografts (PDXs). we identify a subset responsive to EGFR inhibition by gefitinib. which displays heterogeneous expression of wild-type EGFR. https://www.truvisionhealthftp.com/