PO.CL01.02 · 临床研究
单细胞免疫分析揭示早期三阴性乳腺癌帕博利珠单抗疗效的生物标志物
Single-cell immune profiling reveals biomarkers of pembrolizumab response in early triple-negative breast cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：三阴性乳腺癌（TNBC）是一种侵袭性亚型，占所有乳腺癌的15-20%，其特征是早期复发和缺乏靶向治疗。在标准新辅助化疗基础上加用帕博利珠单抗可显著改善结局；然而，临床获益仍存在异质性，且仍缺乏疗效或耐药的预测性生物标志物。
目的：表征早期TNBC中与帕博利珠单抗新辅助治疗疗效和耐药相关的外周免疫细胞状态。
方法：纳入接受帕博利珠单抗联合化疗新辅助治疗的早期TNBC患者。在基线、治疗期间、手术前及手术后一个月采集系列血样。使用10x Chromium平台，通过单细胞RNA测序及配对的TCR/BCR测序分析外周血单个核细胞（PBMC）。在缓解者（定义为残余癌负荷RCB 0的患者）与非缓解者（RCB I-III）之间比较细胞组成、转录状态、检查点表达和克隆结构。
结果：单细胞分析揭示了缓解者与非缓解者在基线时不同的系统性免疫特征。缓解者表现出一种免疫预备状态，其特征为细胞毒性NK细胞和效应T细胞富集，同时初始CD4+ T细胞和调节性T细胞减少。相反，非缓解者则以初始和抑制性群体占主导。在转录水平上，缓解者的CD4+ T细胞表现出较低的基础激活（↓AP-1、↓TNF），但抗原呈递和增殖特征较高。NK细胞和单核细胞区室更具炎症性和代谢活性，而B细胞显示出增强的抗原呈递能力（↑MHC-II、↑CD86）。检查点表达分析显示，缓解者在多个免疫谱系中TIGIT、TIM3和PD-1的平均值和频率更高。TCR测序数据显示缓解者存在寡克隆扩增，与非缓解者多克隆、未扩增的库形成对比。
结论：外周免疫分析揭示了与早期TNBC帕博利珠单抗疗效和耐药相关的不同系统性免疫程序。缓解者表现出抗原经验型、细胞毒性及克隆扩增免疫群体的特征，而耐药病例则显示静止和调节性主导的特征。这些发现凸显了基于免疫的液体活检作为一种微创工具，在乳腺癌中识别免疫治疗疗效和耐药预测性生物标志物的潜力。
查看英文原文 English abstract
Background: Triple-negative breast cancer (TNBC) is an aggressive subtype representing 15-20% of all breast cancers, characterized by early recurrence and lack of targeted therapies. The addition of pembrolizumab to standard neoadjuvant chemotherapy significantly improves outcomes; however, clinical benefit remains heterogeneous and predictive biomarkers of response or resistance are still lacking.
Objectives: To characterize peripheral immune cell states associated with response and resistance to pembrolizumab-based neoadjuvant therapy in early TNBC.
Methods: Patients with early TNBC treated with neoadjuvant pembrolizumab plus chemotherapy were included. Serial blood samples were obtained at baseline, during treatment, before surgery, and one month after surgery. Peripheral blood mononuclear cells (PBMCs) were analyzed by single-cell RNA sequencing and paired TCR/BCR sequencing using the 10x Chromium platform. Cellular composition, transcriptional states, checkpoint expression, and clonal architecture were compared between responders, defined as patients with Residual Cancer Burden (RCB 0) and non-responders (RCB I-III).
Results: Single-cell analysis revealed distinct systemic immune profiles between responders and non-responders at baseline. Responders displayed an immune-prepared state characterized by enriched cytotoxic NK cells and effector T cells, together with reduced naïve CD4+ T cells and regulatory T cells. In contrast, non-responders showed dominance of naïve and suppressive populations. At the transcriptional level, CD4+ T cells from responders exhibited lower basal activation (↓AP-1, ↓TNF) but higher antigen presentation and proliferation signatures. NK and monocyte compartments were more inflammatory and metabolically active, while B cells showed increased antigen-presenting capacity (↑MHC-II, ↑CD86). Checkpoint expression analysis revealed higher mean and frequency of TIGIT , TIM3 , and PD-1 across multiple immune lineages in responders. TCR-seq data showed oligoclonal expansions in responders, contrasting with the polyclonal, unexpanded repertoires of non-responders.
Conclusions: Peripheral immune profiling reveals distinct systemic immune programs associated with response and resistance to pembrolizumab in early TNBC. Responders display features of antigen-experienced, cytotoxic, and clonally expanded immune populations, whereas resistant cases show quiescent and regulatory-dominant profiles. These findings highlight the potential of immune-based liquid biopsy as a minimally invasive tool to identify predictive biomarkers of immunotherapy efficacy and resistance in breast cancer.
利益披露 Disclosure
I. Comino-Mendez, None..
M. Chica-Parrado, None..
M. Quirós-Ortega, None..
A. Godoy-Ortiz, None..
M. Dominguez-Recio, None..
E. López-López, None..
M. Ortega-Jiménez, None..
M. Alvarez, None..
J. Pascual, None..
E. de Alava, None..
E. Alba, None.