Table_1_Case report: A case of rare metastasis of gastric cancer to the axillary lymph node metastasis treated with combination immunotherapy.docx

Lymph node (LN) metastasis is a common mode of metastasis in advanced gastric cancer (GC), while axillary LN metastasis infrequently occurs in GC. There are few reports on this rare type of metastasis – especially its clinicopathological features – and systemic treatment are unclear. We describe a case of GC with extensive metastasis, including the rare axillary LN metastasis. The patient achieved partial response of optimal efficacy, who was treated with combination immunotherapy as second-line treatment for nearly two years. The potential mechanisms were revealed by clinical and immune characteristics, such as high expression of PD-L1, high tumor mutational burden (TMB-H), Epstein-Barr virus (EBV) positive and CD8+ tumor-infiltrating lymphocyte positive.

淋巴结（LN）转移是进展期胃癌（GC）常见的转移途径，而腋窝淋巴结转移在胃癌中较为少见。目前针对这类罕见转移类型（尤其是其临床病理特征）的报道较少，其全身治疗方案尚不明确。本研究报告1例发生广泛转移的胃癌病例，其中包含罕见的腋窝淋巴结转移。该患者接受二线联合免疫治疗近2年，达到了最佳疗效的部分缓解。通过临床及免疫特征分析可揭示其潜在机制，包括程序性死亡受体配体1（PD-L1）高表达、高肿瘤突变负荷（TMB-H）、EB病毒（EBV）阳性以及CD8+肿瘤浸润淋巴细胞阳性。