Identification of genetic and immune signatures for the recurrence of HER2-positive breast cancer after trastuzumab-based treatment

Purpose To determine the genetic and immune features associated with the recurrence of human epidermal growth factor receptor2-positive (HER2 +) breast cancer (BC) after trastuzumab-based treatment. Methods A retrospective cohort study of 48 patients who received trastuzumab-based treatment was divided into recurrent and non-recurrent groups according to clinical follow-up. Baseline samples from all 48 patients were analyzed for genetic variation, HLA allele type, gene expression, and immune features, which were linked to HER2 + BC recurrence. Statistics included logistic regression models, Kaplan–Meier plots, and Univariate Cox proportional hazards models. Results Compared with the non-recurrent group, the extracellular matrix-related pathway and 3 Hallmark gene sets were enriched in the recurrent group. The infiltration levels of immature B cells and activated B cells were significantly increased in the non-recurrent group, which correlated remarkably with improved overall survival (OS) in two other published gene expression datasets, including TCGA and METABRIC. In the TCGA cohort ( n = 275), activated B cells (HR 0.23, 95%CI 0.13–0.43, p