Background
tumors, breast tumor, breast cancer
PROLIFERATION, DEDIFFERENTIATION, TUMORS, BREAST CANCER
Adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) significantly decreases the incidence of ipsilateral breast tumor recurrence (IBTR).CD8+T cells are considered the primary effector cell of the antitumoral immune responseHistological grade has long been an important prognostic factor in breast cancer and primarily measures proliferation and dedifferentiation.This study aimed to investigate whether an integrated analysis of TILs, the PD-1/PD-L1 signaling pathway, and histological grade can identify immune-responsive tumors from a cohort dominated by luminal tumors and inform RT de-escalation. These biomarkers are already being evaluated in clinical practice, and an increased understanding of their interaction for determining RT benefit and immune responsiveness may improve the treatment of patients with breast cancer. Using our previously developed gene expression signature predicting immune responsiveness,