Complex rearrangements fuel ER+ and HER2+ breast tumours
['Houlahan, Kathleen E.', 'Caswell-Jin, Jennifer L.', 'Curtis, Christina']; Nature; 2025年1月8日
『Abstract』Breast cancer is a highly heterogeneous disease whose prognosis and treatment as defined by the expression of three receptors—oestrogen receptor (ER), progesterone receptor and human epidermal growth factor receptor 2 (HER2; encoded by ERBB2 )—is insufficient to capture the full spectrum of clinical outcomes and therapeutic vulnerabilities. Previously, we demonstrated that transcriptional and genomic profiles define eleven integrative subtypes with distinct clinical outcomes, including four ER subtypes with increased risk of relapse decades after diagnosis . Here, to determine whether these subtypes reflect distinct evolutionary histories, interactions with the immune system and pathway dependencies, we established a meta-cohort of 1,828 breast tumours spanning pre-invasive, primary invasive and metastatic disease with whole-genome and transcriptome sequencing. We demonstrate that breast tumours fall along a continuum constrained by three genomic archetypes. The ER high-risk integrative subgroup is characterized by complex focal amplifications, similar to HER2 tumours, including cyclic extrachromosomal DNA amplifications induced by ER through R-loop formation and APOBEC3B-editing, which arise in pre-invasive lesions. By contrast, triple-negative tumours exhibit genome-wide instability and tandem duplications and are enriched for homologous repair deficiency-like signatures, whereas ER typical-risk tumours are largely genomically stable. These genomic archetypes, which replicate in an independent cohort of 2,659 primary tumours, are established early during tumorigenesis, sculpt the tumour microenvironment and are conserved in metastatic disease. These complex structural alterations contribute to replication stress and immune evasion, and persist throughout tumour evolution, unveiling potential vulnerabilities.
『摘要』
乳腺癌是一种高度异质性疾病,目前通过雌激素受体(ER)、孕激素受体和人表皮生长因子受体2(HER2,由ERBB2编码)三种受体的表达来定义的预后和治疗方案,不足以全面反映其临床结果和治疗敏感性。此前,我们发现转录组和基因组特征可界定出具有不同临床结果的11种综合亚型,包括4种在诊断后数十年内复发风险增加的ER亚型。在本研究中,为了确定这些亚型是否反映了不同的进化历程、与免疫系统的相互作用以及通路依赖性,我们建立了一个包含1828例乳腺癌肿瘤的汇总队列,涵盖了癌前病变、原发性浸润癌和转移性癌,并进行了全基因组测序和转录组测序。我们发现,乳腺癌肿瘤属于由三种基因组原型约束的连续体。ER高风险综合亚组的特征为复杂的局灶性扩增,与HER2肿瘤类似,包括由ER通过R环形成和APOBEC3B编辑诱导的细胞外环状DNA周期性扩增,这些扩增发生在癌前病变中。相比之下,三阴性肿瘤表现出全基因组范围的不稳定性和串联重复,并且富含同源修复缺陷样特征,而ER典型风险肿瘤在基因组上则大多稳定。这些基因组原型在包含2659例原发性肿瘤的独立队列中得到复现,它们在肿瘤发生的早期阶段就已确定,塑造了肿瘤微环境,并在转移性癌中保持不变。这些复杂的结构改变会引起复制应激和免疫逃逸,并持续存在于肿瘤进化过程中,从而揭示出潜在的脆弱性。
『总结』
本研究揭示了乳腺癌的三种基因组原型及其与肿瘤进化、免疫相互作用的关系,为乳腺癌的精准治疗提供了新视角。
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