Background: Axillary lymph node (ALN) metastasis is a critical prognostic determinant in breast cancer (BC) that informs surgical management. However, surgically clearing the axilla carries morbidity, so less invasive methods of risk-stratifying patients are needed. ALN fine needle aspiration (FNA) is currently used to detect BC metastases, but these samples also contain immune cells.Methods: Cells obtained via FNA from BC-patient-derived ALNs were analysed using flow cytometry.Results: FNA acquires sufficient leukocytes for comprehensive immunophenotyping of reactive, patient-derived ALNs. All CD4+and CD8+T-cell subsets (naïve, terminal effector, central memory, and effector memory) and rarer (<2%) natural killer (NK) and plasmacytoid dendritic cell (pDC) populations are represented. Importantly, the immune-cell profile of one reactive ALN appears to reflect the immune status of the patient’s axilla. Furthermore, FNA captures immune differences between patients with ≤1 or ≥2 metastatic ALNs. Increased numbers of naïve CD4+T cells, but fewer terminal effector, central memory, and effector memory subpopulations, were obtained from patients with ≥2 metastatic ALNs. Moreover, despite their sparse distribution pattern on whole-section immunohistochemistry (WSI), FNA revealed that CD56+NK cell activation receptors were decreased in patients with ≥2 metastatic ALNs. Finally, FNA captured a decrease in pDCs in patients with ≤1 metastatic ALNs, despite their clustered distribution pattern on WSI.Conclusions: FNA is not only feasible for sampling leukocytes from reactive, patient-derived ALNs, but also identifies immune-cell profiles that reflect axillary tumour burden in BC. Thus, this technique could be used to risk-stratify BC patients in the future.
背景：腋窝淋巴结转移是乳腺癌的重要预后决定因素，并指导外科治疗决策。然而，腋窝淋巴结清扫术会伴随并发症，因此需要更微创的方法对患者进行风险分层。目前腋窝淋巴结细针穿刺抽吸术用于检测乳腺癌转移，但这些样本中也含有免疫细胞。
方法：我们采用流式细胞术对乳腺癌患者腋窝淋巴结细针穿刺抽吸获取的细胞进行分析。
结果：细针穿刺抽吸术可从反应性患者来源的腋窝淋巴结中获取足够数量的白细胞，用于全面的免疫表型分析。所有CD4+和CD8+T细胞亚群、以及较罕见的自然杀伤细胞和浆细胞样树突状细胞亚群均能被检测到。重要的是，一个反应性腋窝淋巴结的免疫细胞特征似乎反映了患者腋窝的整体免疫状态。此外，细针穿刺抽吸术能够捕获转移性腋窝淋巴结数目≤1个和≥2个的患者之间的免疫差异：从转移性腋窝淋巴结≥2个的患者中获取的样本显示，初始CD4+T细胞数量增加，但终末效应、中央记忆和效应记忆T细胞亚群数量减少。尽管免疫组化全切片显示CD56+自然杀伤细胞呈稀疏分布，细针穿刺抽吸术仍揭示转移性腋窝淋巴结≥2个的患者中其激活受体表达降低。最后，尽管浆细胞样树突状细胞在免疫组化全切片上呈簇状分布，细针穿刺抽吸术仍检测到转移性腋窝淋巴结≤1个的患者中该细胞数量减少。
结论：细针穿刺抽吸术不仅可用于从反应性患者来源的腋窝淋巴结中取样白细胞，还能识别反映乳腺癌腋窝肿瘤负荷的免疫细胞特征。因此，该技术未来或可用于乳腺癌患者的风险分层。
Immune Profiling the Axilla with Fine Needle Aspiration Is Feasible to Risk-Stratify Breast Cancer
肿瘤(癌症)患者之家