Tumor-specific MHC-II guides anthracycline exemption and immunotherapy benefit in breast cancer
摘要
Anthracycline-based chemotherapy, while foundational in breast cancer treatment, confers substantial cardiotoxicity. Identifying biomarkers to guide anthracycline exemption without compromising efficacy has remained an unresolved clinical challenge for decades.
MethodsWe conducted multi-cohort spatial-omics and clinical validation integrating 345 early-stage triple-negative breast cancer (eTNBC) and 167 HER2 + breast cancer patients from Fudan University Shanghai Cancer Center (FUSCC) cohorts, alongside 150 eTNBC patients from a validation cohort. Tumor-specific MHC-II (tsMHC-II) expression was quantified via multiplex immunohistochemistry (mIHC). Mechanistic insights were derived from the NeoTRIP immunotherapy spatial cohort, I-SPY2 trial data, TCGA database, ATAC-seq chromatin profiling, ChIP, and patient-derived organoid (PDO)-immune cell co-culture systems.
ResultsIn eTNBC, high tsMHC-II expression predicted improved disease-free survival (DFS) and comparable overall survival (OS) with paclitaxel-carboplatin (PCb) versus anthracycline-sequential paclitaxel (EC-P), identifying tsMHC-II as a predictive marker for anthracycline exemption. High tsMHC-II correlated with prolonged DFS and OS in both TNBC and HER2 + subtypes. Multi-omics including spatial and transcriptional cohorts revealed tsMHC-II-high tumors harbor immune-rich microenvironments with elevated cytotoxic T cells, B cells, and antigen-presenting cells. Validation in NeoTRIP and I-SPY2 cohorts demonstrated superior immunotherapy response in tsMHC-II-high patients. Mechanistically, ATAC-seq, ChIP and PDO co-culture models confirmed that KAT2B upregulated tsMHC-II via CIITA promoter acetylation, sustaining immunotherapeutic vulnerability.
ConclusionTsMHC-II serves as a dual biomarker for adjuvant anthracycline chemotherapy exemption and neoadjuvant immunotherapy stratification in TNBC, driven by KAT2B-mediated epigenetic remodeling. These findings advance precision strategies to reduce anthracycline toxicity while enhancing immune activation in eTNBC.