Background:ESR1mutations are biomarkers in breast cancer patients who develop metastatic disease after endocrine therapy (ET). Recently, the Food and Drug Administration (FDA) and European Medicines Agency (EMA) have approved Elacestrant, a selective estrogen receptor degrader for patients harboringESR1mutations. This has necessitated the establishment of reliable and sensitive NGS- or PCR-based assays to detect theseESR1resistance mutations in liquid biopsy samples. Methods: We evaluated NGS results of a pan-cancer cohort of almost 6000 patients from two major German institutes of pathology, to show that the occurrence ofESR1mutations is extremely rare (<1%) in ET-naïve patients. This suggests thatESR1mutations arise almost exclusively under the pressure of ET. Therefore, we designed a breast cancer-specific hybrid capture-based NGS liquid biopsy assay covering 12 breast cancer-related genes, includingESR1,PIK3CA,AKT1,ERBB2,BRCA1/2, andTP53. We validated the HS2-Mamma-LIQ assay extensively using reference material to detect mutations to 0.1% variant allele frequency (VAF) and compared the performance to a commercially availableESR1ddPCR assay. Results: We show the results of routine diagnostic analysis of the first consecutive 354 patients with activatingESR1mutations rate of 43%, with 20% of patients harboring co-mutations inPIK3CAand other genes underlining the relevance of tumor heterogeneity. Our study highlights liquid biopsy as a preferred approach for monitoringESR1mutations in breast cancer patients by showing cases where NGS analysis suggests complex tumor heterogeneity with multipleESR1as well asPIK3CAmutations at different VAFs. Conclusions: Our findings not only corroborate prior research concerning the rarity of these mutations in unselected patients but also emphasize the importance of robust and broad molecular assays rather than single gene assays in their detection and characterization in the diagnostic setting. Advantages of different approaches are discussed to address the current clinical need.
背景：ESR1突变是乳腺癌患者在接受内分泌治疗（ET）后发生转移性疾病的生物标志物。近期，美国食品药品监督管理局（FDA）和欧洲药品管理局（EMA）已批准选择性雌激素受体降解剂Elacestrant用于携带ESR1突变的患者。这要求建立可靠且灵敏的基于NGS或PCR的检测方法，以在液体活检样本中检测这些ESR1耐药突变。方法：我们评估了来自德国两家主要病理研究所的近6000名泛癌队列患者的NGS结果，显示ESR1突变在未接受过ET治疗的患者中极为罕见（<1%）。这表明ESR1突变几乎完全是在ET治疗压力下产生的。因此，我们设计了一种基于杂交捕获的乳腺癌特异性NGS液体活检检测方法，覆盖12个乳腺癌相关基因，包括ESR1、PIK3CA、AKT1、ERBB2、BRCA1/2和TP53。我们使用参考材料对HS2-Mamma-LIQ检测方法进行了广泛验证，以检测低至0.1%变异等位基因频率（VAF）的突变，并将其性能与市售的ESR1 ddPCR检测方法进行了比较。结果：我们展示了首批连续354例患者的常规诊断分析结果，其中激活型ESR1突变率为43%，20%的患者同时携带PIK3CA及其他基因的共突变，凸显了肿瘤异质性的重要性。通过展示NGS分析提示复杂肿瘤异质性的病例，包括不同VAF下的多个ESR1及PIK3CA突变，我们的研究强调了液体活检作为监测乳腺癌患者ESR1突变的优选方法。结论：我们的发现不仅证实了先前关于这些突变在未筛选患者中罕见的研究，还强调了在诊断环境中使用稳健且广泛的分子检测方法而非单基因检测的重要性。我们讨论了不同方法的优势，以应对当前的临床需求。
肿瘤(癌症)患者之家