Background

Bladder cancer (BC) can be successfully treated by manipulating immune responses with intravesical Bacillus Calmette-Guerin instillation or targeting the PD-1/PD-L signaling pathway. In the present study we investigated the prognostic significance of the immune checkpoint inhibitor PD-1 and its ligands PD-L1 and PD-L2 on tumor cells and infiltrating lymphocytes, in the tumor microenvironment and draining lymph nodes in patients with non-metastatic BC.

Patients and methods

Cells were mechanically isolated from tissues and draining lymph nodes from 58 patients, and surface-stained for CD45, PD-1, PD-L1 and PD-L2. The cells were then analyzed with a flow cytometric method.

Results

Approximately 2% of CD45-negative tumor and stromal cells expressed PD-L1. Expression was not associated with the main clinicopathological characteristics of the disease or with survival. However, as tumors progressed the frequency of PD-L1⁺CD45^hi cells and the mean expression of PD-1 on CD45^hi cells increased remarkably on immune cells in tumor tissues and draining lymph nodes. In addition, frequency analysis showed that cell percentages as well as mean expression of PD-L2 on total CD45⁺ lymphocytes and their CD45^hi subpopulation in tumor-draining lymph nodes was significantly associated with cancer-related death (P < 0.05). Multiple Cox regression also revealed that while CD45⁺ (hazard ratio: 0.596, 95 % CI 0.439–0.809, P = 0.001) was associated with improved survival, CD45^neg (HR: 0.615, 95 % CI 0.454–0.831, P = 0.002), and PD-L2⁺CD45⁺ cells (hazard ratio: 1.472, 95 % CI 1.023–2.120, P = 0.038) in draining lymph nodes were associated with lower survival.

Conclusion

Our results suggest that in patients with BC, PD-1 and PD-L expression on immune cells, especially in draining lymph nodes, is valuable for predicting prognosis and survival, and possibly responsiveness to immunotherapy. However, expression of the inhibitor molecule or its ligands on tumor cells was not associated with prognosis. The results highlight the significance of PD-L2 as a second important suppressive molecule in tumors.

中文翻译：

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PD-1 / PD-Ls在非转移性膀胱癌中的临床相关性和预后意义：PD-L2的作用。

背景

膀胱癌（Calmette-Guerin）膀胱内滴注操纵免疫反应或靶向PD-1 / PD-L信号通路可以成功治疗膀胱癌（BC）。在本研究中，我们调查了非转移性BC患者的免疫检查点抑制剂PD-1及其配体PD-L1和PD-L2对肿瘤微环境和引流淋巴结中肿瘤细胞和浸润淋巴细胞的预后意义。

患者和方法

从58例患者的组织和引流淋巴结中机械分离细胞，并对CD45，PD-1，PD-L1和PD-L2进行表面染色。然后用流式细胞仪分析细胞。

结果

大约2％的CD45阴性肿瘤和基质细胞表达PD-L1。表达与疾病的主要临床病理特征或生存无关。然而，由于肿瘤进展PD-L1的频率⁺ CD45^喜细胞和PD-1的上CD45的平均表达^喜细胞对肿瘤组织的免疫细胞和引流淋巴结显着提高。此外，频率分析表明，肿瘤引流淋巴结中总CD45 ⁺淋巴细胞及其CD45 ^hi亚群中细胞百分比以及PD-L2的平均表达与癌症相关的死亡显着相关（P <0.05）。多重Cox回归也显示CD45 ⁺（危险比：0.596，95％CI 0.439-0.809，P = 0.001）与存活率提高，CD45 ^neg（HR：0.615，95％CI 0.454-0.831，P = 0.002）和PD-L2 ⁺ CD45 ⁺细胞相关（引流淋巴结中的危险比：1.472，95％CI 1.023–2.120，P = 0.038）与较低的生存率相关。

结论

我们的结果表明，在患有BC的患者中，免疫细胞（尤其是引流淋巴结）中的PD-1和PD-L表达对于预测预后和存活率以及可能对免疫疗法的反应具有重要意义。然而，抑制剂分子或其配体在肿瘤细胞上的表达与预后无关。结果突出了PD-L2作为肿瘤中第二重要抑制分子的重要性。