Gastric cancer (GC) is a common tumor with a low 5‐year survival rate. The chemokine receptor 4 (CXCR4) protein contributes to the progression and prognosis of GC, but the relationship between CXCR4 and immune infiltration, somatic copy number alteration (SCNA), tumor purity, tumor mutation burden (TMB), cytolytic activity (CYT), and drug sensitivity in GC is poorly understood. This study aimed to systematically explore the role of CXCR4 in GC. Microarray and RNA‐seq data were collected from the Gene Expression Omnibus and The Cancer Genome Atlas. Our analysis shows that CXCR4 is correlated with various types of immune cells. Patients with high CXCR4 expression had a higher fraction of B cells and CD8⁺ T cells, and a lower fraction of CD4⁺ T cells. In addition, high CXCR4 expression was associated with more advanced tumor stage, worse prognosis and higher stromal score, immune score, and cytolytic activity (P < 0.05). High CXCR4 expression also correlated with lower tumor purity and TMB. In summary, our analyses suggest that CXCR4 may affect the progression and prognosis of GC by influencing immune infiltration, TMB, CYT, tumor purity, and drug sensitivity.

中文翻译：

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趋化因子受体4表达与胃癌的发生及预后相关。

胃癌（GC）是一种常见肿瘤，5年生存率较低。趋化因子受体4（CXCR4）蛋白有助于GC的进展和预后，但CXCR4与免疫浸润、体细胞拷贝数改变（SCNA）、肿瘤纯度、肿瘤突变负荷（TMB）、细胞溶解活性（CYT）、对于 GC 的药物敏感性知之甚少。本研究旨在系统探讨CXCR4在GC中的作用。微阵列和 RNA-seq 数据是从基因表达综合和癌症基因组图谱中收集的。我们的分析表明 CXCR4 与各种类型的免疫细胞相关。^{CXCR4 高表达的患者 B 细胞和 CD8 +} T 细胞比例较高，CD4 ⁺ T 细胞比例较低。此外，CXCR4 高表达与肿瘤分期更晚期、预后更差以及基质评分、免疫评分和溶细胞活性更高相关（P  < 0.05）。高 CXCR4 表达还与较低的肿瘤纯度和 TMB 相关。总之，我们的分析表明CXCR4可能通过影响免疫浸润、TMB、CYT、肿瘤纯度和药物敏感性来影响GC的进展和预后。