Department of Dermatology, University Medical Center of the Johannes-Gutenberg University, Mainz, Germany.
Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States.
Front Immunol. 2023 Apr 28;14:1070203. doi: 10.3389/fimmu.2023.1070203. eCollection 2023.
Effective anti-tumor immune responses are mediated by T cells and require organized, spatially coordinated interactions within the tumor microenvironment (TME). Understanding coordinated T-cell-behavior and deciphering mechanisms of radiotherapy resistance mediated by tumor stem cells will advance risk stratification of oropharyngeal cancer (OPSCC) patients treated with primary chemoradiotherapy (RCTx).
To determine the role of CD8 T cells (CTL) and tumor stem cells for response to RCTx, we employed multiplex immunofluorescence stains on pre-treatment biopsy specimens from 86 advanced OPSCC patients and correlated these quantitative data with clinical parameters. Multiplex stains were analyzed at the single-cell level using QuPath and spatial coordination of immune cells within the TME was explored using the R-package Spatstat.
Our observations demonstrate that a strong CTL-infiltration into the epithelial tumor compartment (HR for overall survival, OS: 0.35; p<0.001) and the expression of PD-L1 on CTL (HR: 0.36; p<0.001) were both associated with a significantly better response and survival upon RCTx. As expected, p16 expression was a strong predictor of improved OS (HR: 0.38; p=0.002) and correlated with overall CTL infiltration (r: 0.358, p<0.001). By contrast, tumor cell proliferative activity, expression of the tumor stem cell marker CD271 and overall CTL infiltration, regardless of the affected compartment, were not associated with response or survival.
In this study, we could demonstrate the clinical relevance of the spatial organization and the phenotype of CD8 T cells within the TME. In particular, we found that the infiltration of CD8 T cells specifically into the tumor cell compartment was an independent predictive marker for response to chemoradiotherapy, which was strongly associated with p16 expression. Meanwhile, tumor cell proliferation and the expression of stem cell markers showed no independent prognostic effect for patients with primary RCTx and thus requires further study.
有效的抗肿瘤免疫反应是由 T 细胞介导的，需要在肿瘤微环境（TME）内进行有组织的、空间协调的相互作用。了解 T 细胞的协调行为，并破译肿瘤干细胞介导的放射治疗抵抗的机制，将推进接受原发放化疗（RCTx）治疗的口咽鳞癌（OPSCC）患者的风险分层。
为了确定 CD8 T 细胞（CTL）和肿瘤干细胞对 RCTx 反应的作用，我们对 86 例晚期 OPSCC 患者的治疗前活检标本进行了多重免疫荧光染色，并将这些定量数据与临床参数相关联。使用 QuPath 在单细胞水平上分析多重染色，并使用 R 包 Spatstat 探索免疫细胞在 TME 中的空间协调。
我们的观察结果表明，CTL 强烈浸润上皮肿瘤区（总体生存的 HR：0.35；p<0.001）和 CTL 上 PD-L1 的表达（HR：0.36；p<0.001）均与 RCTx 后反应和生存的显著改善相关。正如预期的那样，p16 表达是 OS 改善的有力预测指标（HR：0.38；p=0.002），并与总体 CTL 浸润相关（r：0.358，p<0.001）。相比之下，肿瘤细胞增殖活性、肿瘤干细胞标志物 CD271 的表达以及整体 CTL 浸润，无论受影响的部位如何，均与反应或生存无关。
在这项研究中，我们能够证明 CD8 T 细胞在 TME 中的空间组织和表型与临床相关。特别是，我们发现 CTL 特异性浸润肿瘤细胞区是对放化疗反应的独立预测标志物，与 p16 表达强烈相关。同时，肿瘤细胞增殖和干细胞标志物的表达对接受原发 RCTx 的患者没有独立的预后影响，因此需要进一步研究。
