Objective. Gastroesophageal adenocarcinoma (GEA) is a high deadly and heterogeneous cancer. RNA N6-methyladenosine (m⁶A) modification plays a non-negligible role in shaping individual tumour microenvironment (TME) characterizations. However, the landscape and relationship of m⁶A modification patterns and TME cell infiltration features remain unknown in GEA. Methods. In this study, we examined the TME of GEA using assessments of the RNA-sequencing data focusing on the distinct m⁶A modification patterns from the public databases. Intrinsic patterns of m⁶A modification were evaluated for associations with clinicopathological characteristics, underlying biological pathways, tumour immune cell infiltration, oncological outcomes, and treatment responses. The expression of key m⁶A regulators and module genes was validated by qRT-PCR analysis. Results. We identified two distinct m⁶A modification patterns of GEA (cluster 1/2 subgroup), and correlated two subgroups with TME cell-infiltrating characteristics. Cluster 2 subgroup correlates with a poorer prognosis, downregulated PD-1 expression, higher risk scores, and distinct immune cell infiltration. In addition, PPI and WGCNA network analysis were integrated to identify key module genes closely related to immune infiltration of GEA to find immunotherapy markers. COL4A1 and COL5A2 in the brown module were significantly correlated to the prognosis, PD-1/L1 and CTLA-4 expression of GEA patients. Finally, a prognostic risk score was constructed using m⁶A regulator-associated signatures that represented an independent prognosis factor for GEA. Interestingly, COL5A2 expression was linked to the response to anti-PD-1 immunotherapy, m⁶A regulator expression, and risk score. Conclusion. Our work identified m⁶A RNA methylation regulators as an important class of players in the malignant progression of GEA and were associated with the complexity of the TME. COL5A2 may be the potential biomarker which contributes to predicting the response to anti-PD-1 immunotherapy and patients’ prognosis.

中文翻译：

---

N6-甲基腺苷 (m6A) RNA 甲基化调节剂和肿瘤微环境细胞浸润的综合分析涉及胃食管腺癌的预后和免疫治疗

目标。胃食管腺癌 (GEA) 是一种高致死性和异质性癌症。RNA N6-甲基腺苷 (m ⁶ A) 修饰在塑造个体肿瘤微环境 (TME) 特征方面起着不可忽视的作用。然而，m ⁶ A 修饰模式和 TME 细胞浸润特征的概况和关系在 GEA 中仍然未知。方法。在这项研究中，我们使用 RNA 测序数据的评估来检查 GEA 的 TME，重点关注公共数据库中不同的 m ⁶ A 修饰模式。^{m 6}的内在模式对修饰与临床病理学特征、潜在生物学途径、肿瘤免疫细胞浸润、肿瘤学结果和治疗反应的关联进行了评估。通过 qRT-PCR 分析验证关键 m ^{6 A 调节因子和模块基因的表达。}结果。我们确定了两个不同的 m ⁶GEA（簇 1/2 亚组）的修饰模式，并将两个亚组与 TME 细胞浸润特征相关联。聚类 2 亚组与较差的预后、下调的 PD-1 表达、较高的风险评分和明显的免疫细胞浸润相关。此外，结合PPI和WGCNA网络分析，识别与GEA免疫浸润密切相关的关键模块基因，寻找免疫治疗标志物。棕色模块中的COL4A1和COL5A2与GEA患者的预后、PD-1/L1和CTLA-4表达显着相关。最后，使用代表 GEA 独立预后因素的m ⁶ A 监管机构相关特征构建了预后风险评分。有趣的是，COL5A2 表达与对抗 PD-1 免疫疗法的反应有关，m⁶调节器表达和风险评分。结论。我们的工作确定了 m ⁶ A RNA 甲基化调节因子是 GEA 恶性进展中的一类重要参与者，并且与 TME 的复杂性相关。COL5A2可能是潜在的生物标志物，有助于预测抗PD-1免疫疗法的反应和患者的预后。