Bladder cancer (BLCA) remains a difficult malignancy to manage because of its high recurrence, intense follow-up, and invasive diagnostic and treatment techniques. Immune checkpoint inhibitors (ICIs) have forged a new direction for the treatment of BLCA, but it is currently challenging to predict whether an individual patient will be sensitive to ICIs. We collected 43 urine/tumor samples from BLCA patients for primary bladder cancer cells (BCCs) culturing using our previously reported BCC culture platform. We used flow cytometry (FCM) to measure the expression levels of Programmed Death-Ligand 1 (PD-L1) on BCCs before and after interferon-gamma (IFN-γ) treatment and found that PD-L1 expression and the sensitivities to IFN-γ varied among patients. RNA-sequencing, western blotting, and programmed death-1 (PD-1) binding assays confirmed that the BCC FCM-based PD-L1 detection platform (BC-PD-L1) was reliable and was not hindered by the glycosylation of PD-L1. In the subsequent retrospective study, we found that IFN-γ-stimulated PD-L1 (sPD-L1) expression on BCCs detected by BC-PD-L1 could predict the prognosis of BLCA patients. Importantly, the prognostic value was similar or even better in urine-derived BC-PD-L1 (UBC-PD-L1). Transcriptome analysis showed that BCCs with high sPD-L1 tended to enrich genes associated with the collagen-containing extracellular matrix, cell–cell adhesion, and positive regulation of the immune system. In addition, the UBC-PD-L1 also exhibited predictive value for ICI response in BLCA patients. In conclusion, as a novel personalized urine-detection method, UBC-PD-L1 may provide a rapid, accurate, and non-invasive tool for monitoring tumor progression, predicting therapeutic responses, and helping improve BLCA clinical treatment in future.

膀胱癌（BLCA）由于其高复发率、频繁的随访以及侵入性诊断和治疗技术，仍然是一种难以治疗的恶性肿瘤。免疫检查点抑制剂（ICIs）为 BLCA 的治疗开辟了新方向，但目前预测个体患者是否会对 ICI 敏感仍具有挑战性。我们从 BLCA 患者收集了 43 份尿液/肿瘤样本，使用我们之前报道的 BCC 培养平台进行原发性膀胱癌细胞 (BCC) 培养。我们采用流式细胞术（FCM）检测干扰素-γ（IFN-γ）治疗前后BCC上程序性死亡配体1（PD-L1）的表达水平，发现PD-L1的表达与对IFN-γ的敏感性有关。 γ 因患者而异。RNA 测序、蛋白质印迹和程序性死亡 1 (PD-1) 结合测定证实，基于 BCC FCM 的 PD-L1 检测平台 (BC-PD-L1) 是可靠的，并且不受 PD-1 糖基化的阻碍。 L1。在随后的回顾性研究中，我们发现BC-PD-L1检测到的BCC上IFN-γ刺激的PD-L1（sPD-L1）表达可以预测BLCA患者的预后。重要的是，尿液来源的 BC-PD-L1 (UBC-PD-L1) 的预后价值相似甚至更好。转录组分析表明，具有高 sPD-L1 的 BCC 倾向于富集与含胶原的细胞外基质、细胞间粘附和免疫系统正向调节相关的基因。此外，UBC-PD-L1 还对 BLCA 患者的 ICI 反应表现出预测价值。总之，UBC-PD-L1作为一种新型的个性化尿液检测方法，可能为监测肿瘤进展、预测治疗反应、帮助改善未来的BLCA临床治疗提供一种快速、准确、无创的工具。