Renal cell carcinoma (RCC), one of the top 10 causes of cancer death, is responsible for more than 90% of all cases of primary renal cancer worldwide. Follicular dendritic cell-secreted protein (FDC-SP) specifically binds to activated B cells and regulates the generation of antibodies. It is also thought to promote cancer cell invasion and migration, which could help with tumor metastases. This study aimed to assess the efficacy of FDC-SP in the diagnosis and prognosis of RCC and to investigate the relationship between immune infiltration in RCC and these outcomes. RCC tissues had significantly higher levels of FDC-SP protein and mRNA than normal tissues. The high level of FDC-SP expression was linked to the T stage, histological grade, pathological stage, N stage, M stage, and OS event. Functional enrichment analysis identified the major pathways that were enriched as immune response regulation, complement, and coagulation. Immunological checkpoints and immune cell infiltration were observed to substantially correlate with the levels of FDC-SP expression. FDC-SP expression levels showed the ability to precisely distinguish high-grade or high-stage renal cancer (area under the curve (AUC) = 0.830, 0.722), and RCC patients with higher FDC-SP expression levels had worse prognoses. The AUC values for one-, two-, and five-year survival rates were all greater than 0.600. Moreover, the FDC-SP expression is an independent predictive biomarker of OS in RCC patients. FDC-SP may be a prospective therapeutic target in RCC as well as a possible diagnostic and prognostic biomarker associated with immune infiltration.

中文翻译：

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FDC-SP 作为诊断和预后生物标志物并调节肾细胞癌的免疫浸润

肾细胞癌 (RCC) 是导致癌症死亡的十大原因之一，占全球所有原发性肾癌病例的 90% 以上。滤泡树突细胞分泌蛋白 (FDC-SP) 特异性结合活化的 B 细胞并调节抗体的产生。它也被认为可以促进癌细胞的侵袭和迁移，这可能有助于肿瘤转移。本研究旨在评估 FDC-SP 在 RCC 诊断和预后中的疗效，并探讨 RCC 中免疫浸润与这些结果之间的关系。RCC 组织的 FDC-SP 蛋白和 mRNA 水平显着高于正常组织。FDC-SP 的高水平表达与 T 分期、组织学分级、病理分期、N 分期、M 分期和 OS 事件有关。功能富集分析确定了被富集为免疫反应调节、补体和凝血的主要途径。观察到免疫检查点和免疫细胞浸润与 FDC-SP 表达水平显着相关。FDC-SP表达水平显示能够精确区分高级别或高分期肾癌（曲线下面积（AUC）= 0.830，0.722），FDC-SP表达水平较高的RCC患者预后较差。一年、两年和五年生存率的 AUC 值均大于 0.600。此外，FDC-SP 表达是 RCC 患者 OS 的独立预测生物标志物。FDC-SP 可能是 RCC 的前瞻性治疗靶点，也是与免疫浸润相关的可能的诊断和预后生物标志物。