PD-L1 Expression In Tumor Microenvironment Research Articles

Baicalein enhances immune response in TNBC by inhibiting leptin expression of adipocytes.

Triple-negative breast cancer (TNBC) is a special pathological type of breast cancer (BC) with poor prognosis. Obesity is shown to be involved in TNBC tumor progression. The interaction between obesity and BC has generated great attention in recent years, however, the mechanism is still unclear. Here, we showed that leptin secreted by adipocytes upregulated PD-L1 expression in TNBC through the p-STAT3 signaling pathway and that baicalein inhibited PD-L1 expression in tumor microenvironment by suppressing leptin transcription of adipocytes. Collectively, our findings suggest that leptin may be the key factor participating in obesity-related tumor progression and that baicalein can break through the dilemma to boost the anti-tumor immune response.

Tumor-TME Bipartite Landscape of PD-1/PD-L1 in Endometrial Cancers.

The bipartite landscape of tumor cells and stromal cells determines a tumor's response to treatment during disease management. In endometrial cancers (ECs), the mechanistic contribution of PD-L1/L2 and PD-1 signaling of the host's tumor microenvironment (TME) (CAF and immune cells) in the context of the tumor cells is elusive. To understand the tumor-stroma-immune crosstalk, we studied the compartmental pattern of PD-L1/L2 and PD-1 expression in EC tissues and their matched CAFs. Over 116 surgically resected tumors (T) and the tumor-adjacent normal tissues (N) were obtained from consented unselected consecutive patients. IHC was performed in T, N-epi-thelium, and the stromal mesenchymal environment (SME; mesenchyme) in the T and N tissues. The staining intensity and distribution patterns of PD-L1/L2 and PD-1 in the FFPE sections of T and N were evaluated by a pathologist using a standard scoring system of TPS and CPS. We tested the PD-L1/L2 and PD-1 immune landscape of tumor-TME pair and normal epithelial-stromal mesenchyme pairs from patients with different grades of disease vis-à-vis their CAF PD-L1 levels. We used qRT-PCR to determine the expressions of mRNAs, while the flow cytometry and ICC determined the level of expression of proteins. We observed higher levels of PD-L1 mRNA and protein expression in primary CAFs from the resected tumor tissue compared to the tumor-adjacent normal tissues. We also determined the expression of patients' soluble PD-L1/L2 as peripheral readouts of PD-L1/L2 and PD-1. As we evaluated the results in the context of their pathological parameters, such as grades, stages, lymphovascular invasion, percentage of myometrial invasion, and dMMR in patients, the dominance of PD-L1 expression in TME was positively correlated to the higher pathological grades of tumors, and its relationship with the dMMR. Since the neutralization of CD8-positive cytotoxic T-cells is PD-L1-dependent, our data indicate that irrespective of the PD-L1 positivity of tumor cells, the PD-L1-positive CAFs can play a critical role in bringing out an additional load of PD-L1 for an effective engagement of PD-1 within a tumor mass.

Consistent expression of PD-L1 in tumor microenvironment with peripheral PD-1/PD-L1 in circulating T lymphocytes of operable breast cancer: a diagnostic test

BackgroundThe expression of PD-L1 in the immune microenvironment can guide the application of immunosuppressants. In order to monitor the immune status of the body, repeated biopsies have to be taken. Our research aims to find new and convenient means to evaluate this indicator.MethodsEighty-three cases of newly diagnosed operable breast cancer without receiving preoperative treatment, were recruited from Beijing Shijitan Hospital between November 2018 and November 2019. The expression of PD-1/PD-L1 on circulating T lymphocytes was detected by flow cytometry and the expression of PD-L1 on immune cells in tumor microenvironment was detected by immunohistochemistry.ResultsThe median percentage of positive PD-1 and PD-L1 expression on circulating T lymphocytes was 15.2% and 0.7%, respectively. The peripheral PD-1 had no relationship with clinicopathological characteristics, but the peripheral PD-L1 expression had a correlation with lymph node metastasis (p = 0.005) and Her-2 expression (p = 0.034) (p < 0.05). The positive rate of PD-L1 expression was 32.9% in tumor microenvironment. PD-L1 expression in tumor microenvironment had a significant correlation with PD-1/PD-L1 expression on circulating T lymphocytes, the correlation coefficients being 0.24 (p < 0.05) and 0.26 (p < 0.05), respectively. To predict the PD-L1 expression in tumor microenvironment, the area under the receiver operating characteristic curve was 0.65 and 0.66 for peripheral PD-1 and PD-L1, respectively. High level of peripheral PD-1/PD-L1 expression was associated with the odds ratios of 5.42 and 4.76 for positive PD-L1 expression in tumor microenvironment.ConclusionPeripheral PD-1/PD-L1 expression had a significant consistency with PD-L1 expression in tumor microenvironment and could act as an alternative choice of tissue detection, for the patients intolerable of biopsy.

Histone deacetylase 2 knockout suppresses immune escape of triple-negative breast cancer cells via downregulating PD-L1 expression

The PD-L1 overexpression is an important event of immune escape and metastasis in triple-negative breast cancer (TNBC), but the molecular mechanism remains to be determined. Interferon gamma (IFNγ) represents a major driving force behind PD-L1 expression in tumor microenvironment, and histone deacetylase 2 (HDAC2) is required for IFN signaling. Here, we investigated the regulation of HDAC2 on the IFNγ-induced PD-L1 expression in TNBC cells. We found the HDAC2 and PD-L1 expression in TNBC was significantly higher than that in non-TNBC, and HDAC2 was positively correlated with PD-L1 expression. HDAC2 promoted PD-L1 induction by upregulating the phosphorylation of JAK1, JAK2, and STAT1, as well as the translocation of STAT1 to the nucleus and the recruitment of STAT1 to the PD-L1 promoter. Meanwhile, HDAC2 was recruited to the PD-L1 promoter by STAT1, and HDAC2 knockout compromised IFNγ-induced upregulation of H3K27, H3K9 acetylation, and the BRD4 recruitment in PD-L1 promoter. In addition, significant inhibition of proliferation, colony formation, migration, and cell cycle of TNBC cells were observed following knockout of HDAC2 in vitro. Furthermore, HDAC2 knockout reduced IFNγ-induced PD-L1 expression, lymphocyte infiltration, and retarded tumor growth and metastasis in the breast cancer mouse models. This study may provide evidence that HDAC2 promotes IFNγ-induced PD-L1 expression, suggesting a way for enhanced antitumor immunity when targeting the HDAC2 in TNBC.

Nivolumab in Primary CNS Lymphoma and Primary Testicular Lymphoma with CNS Involvement: Single Center Experience

Background.Most patients with primary CNS lymphoma (PCNSL), an aggressive extranodal lymphoma confined to the CNS, have a poor prognosis in spite of development of chemotherapy regimens. First-line treatment consists of high-dose methotrexate-based (HD-MTX) regimen followed by consolidation with autologous stem cell transplantation or whole brain radiotherapy. Given that this tumor manifests predominantly in older patients with median age of 65 years, many patients are unable to tolerate intensive chemotherapy. Moreover, most patients eventually present with relapsed or refractory (r/r) disease. Relapse or refractory (r/r) PCNSL has a poor prognosis with median overall survival not exceeding 3.5 months (Langner-Lemercier et al, 2016) and these patients should be offered a clinical trial whenever possible. These groups are in need of safe, tolerable and effective therapeutic approaches. Primary testicular lymphoma (PTL) shares biological and clinical similarities with PCNSL and often present with CNS involvement. Such patients are also in need of new approaches, especially if they are refractory or not suitable to HD-MTX. Given high PD-1/PD-L1 expression in tumor microenvironment (Berghoff, 2014), immune checkpoint inhibitors were successfully tested in r/r PCNSL and PTL setting. However, data are still scarce and limited to case series (Nayak et al., 2017; Graber et al. 2020). Here we present Pavlov University experience of the treatment of PCNSL and PTL with CNS involvement with PD-1 inhibitor nivolumab. Methods.Eight patients, 2 men and 6 women, with PCNSL and one patient with PTL with CNS involvement treated at the Pavlov University between 2017 and 2020 were included into analysis. Median age at a diagnosis was 62 (28-66) years. Two patients (22%) had ECOG score 3-4 and therefore could not be considered for intensive MTX containing frontline treatment. In all of the cases the tumor histological type was diffuse large B-cell lymphoma. All patients had parenchymal involvement: 7 patients had multifocal disease; deep structures were involved in 2 patients. One patient had leptomeningeal involvement. Nivolumab was used in a first-line setting in 2 patients (22%). In 7 (78%) patients with relapsed/refractory disease, the median number of treatment lines prior to nivolumab was 1 (1-7). Nivolumab was given every 2 weeks in the 100 mg dose. Adverse events were defined according to NCI CTC-AE 5.0. Results.At the time of analysis, the median follow-up was 18 (3-44) months. Median number of nivolumab cycles was 10 (2-23). Seven (78%) patients had an objective response: complete response in 3 patients (33.3%) and partial response in 4 patients (44.4%). Two patients (22.2%) were refractory to treatment. Two-year overall survival (OS) was 44% with median OS of 12 months. Two-year progression-free survival (PFS) was 26% with median of PFS 12 months. Оne responder had a moderate increase of tumor volume on MRI after two months of therapy followed by complete disappearance of brain lesions on sequential imaging at 4 months after treatment initiation. Nivolumab therapy appeared safe with only one patient (11%) having severe adverse event, namely grade 3 alanine aminotransferase and aspartate aminotransferase increase. Conclusion.Nivolumab appears to be safe and effective therapy in PCNSL and PTL with CNS involvement both in first-line and r/r setting. However, in our cohort majority of patients relapsed that suggest that consolidation therapy after remission induction with nivolumab may be crucial for long-term remissions. We also demonstrate that pseudoprogression might be also observed in PCNSL during immunotherapy. Large-scale trials are needed to generate strong evidence for the use of PD-1 inhibitors in PCNSL. Disclosures No relevant conflicts of interest to declare. OffLabel Disclosure: Nivolumab is an anti-PD-1 inhibitor approved for classical Hodgkin lymphoma. There is early clinical data suggesting the efficiency of nivolumab in PCNS lymphoma (Nayak, 2017)

Prognostic Analysis of NSCLC Based on the Tumor-associated Macrophages, Tumor Neo-vessels and PD-L1 Expression in Tumor Microenvironment

背景与目的肿瘤微环境是肿瘤细胞赖以生存的复杂环境。其中肿瘤相关巨噬细胞（tumor-associated macrophages, TAMs）、肿瘤新生血管及程序性死亡受体1/程序性死亡受体-配体1（programmed cell death protein 1/programmed cell death ligand 1, PD-1/PD-L1）作为关键部分，在肿瘤发生、发展过程中起重要作用，影响患者预后。本研究旨在阐明TAMs、肿瘤新生血管和PD-L1的表达与非小细胞肺癌（non-small cell lung cancer, NSCLC）临床病理特征的相关性，并探讨它们对NSCLC预后的影响。方法收集92例NSCLC患者的临床病理资料及手术标本，采用免疫组化法检测癌组织和癌旁组织中TAMs、肿瘤新生血管和PD-L1的表达，采用配备有Olympus-DP72图像采集系统的Olympus-BX51正置显微镜进行拍照并用Image-pro Plus 6.0软件进行半定量分析。结果癌组织与癌旁组织中TAMs、肿瘤新生血管和PD-L1的表达差异无统计学意义（P > 0.05）。根据肿瘤微环境中各组分的定量表达，可将其分为低、中、高表达组。癌组织中TAMs的低、中和高密度组的中位总生存（overall survival, OS）分别是36个月（95%CI: 25.3-46.7）、26个月（95%CI: 12.2-39.8）和16个月（95%CI: 9.4-22.6），差异具有统计学意义（P=0.016）；肿瘤新生血管的低、中和高密度组的中位OS分别为30个月（95%CI: 22.5-37.5）、28个月（95%CI: 18.1-37.9）和25个月（95%CI: 14.6-35.4），差异无统计学意义（P=0.626）；PD-L1的低、中和高表达组的中位OS分别为35个月（95%CI: 29.4-40.6），28个月（95%CI: 13.6-42.4）和17个月（95%CI: 10.5-23.5），差异具有统计学意义（P=0.002）。联合低、中和高表达组的中位OS分别为36个月（95%CI: 30.6-41.4）、26个月（95%CI: 19.2-32.8）和9个月（95%CI: 4.4-13.6），差异具有统计学意义（P=0.001）。Cox回归分析结果显示，病理分型、TAMs和PD-L1均为肺癌患者的独立预后因素。结论肿瘤微环境关键成分PD-L1及TAMs的表达与NSCLC患者的预后密切相关。

Abstract P4-06-22: Transcription factor T-bet and PD-L1 expression in tumor microenvironment of triple-negative breast cancer

Abstract Background: Many analyzes regarding immunotherapies using checkpoint blockade has made it clear that tumor infiltrating lymphocytes (TILs) plays an important role in treating cancers with high levels of somatic mutations such as triple-negative breast cancer (TNBC). We reported the relationship between TILs and PD-L1 expression, and revealed that high-TILs/positive-PD-L1 expression population in TNBC was associated with better prognosis (Oncotarget 2017). However, its molecular mechanism is still unclear. Meanwhile, T-box transcription factor 21 (T-bet) which regulates effecter T-cells activation is derived by stimulation of T-cell receptor and IL-12. Activated T-cells work as antitumor lymphocytes by enhancing the production of cytokines such as INFγ. We focused on T-bet and examined the function of activated T-cells. Patients and Methods: This study included 242 patients with primary TNBC who underwent resection without neoadjuvant chemotherapy at our three hospitals between January 2004 and December 2014. The immunohistochemistry scoring for CD8 and T-bet expression on TILs was defined as ≥30 per 0.00625mm2. PD-L1 positivity was defined as ≥1% of tumor cells staining positive for PD-L1. Results: Of the 242 TNBC, CD8 on TILs was expressed as positive in 127 (52.5%) tumors, T-bet on TILs was expressed as positive in 67 (27.7%) tumors, and PD-L1 expression on tumor cells was expressed as positive in 99 (40.9%) tumors. T-bet expression was significantly correlated with CD8 expression (P&amp;lt;0.0001) and PD-L1 expression (P=0.0004). There was no significant difference in recurrence free survival (RFS) and overall survival (OS) regardless of CD8 or PD-L1expression level. Meanwhile, the patients with T-bet-positive tumors had a longer OS, compared to those with T-bet-negative tumors (P = 0.13 in RFS and P = 0.047 in OS). The multivariate analysis revealed that T-bet expression on TILswas an independent and positive prognostic factor for OS(HR = 0.5, 95%CI 0.1-0.9, P = 0.035). Conclusion: OS was significantly longer among patients with high T-bet expressing TNBC. These results may validate the significance of T-bet as a biomarker for various immunotherapies in TNBC. Citation Format: Mori H, Kubo M, Kai M, Kurata K, Kawaji H, Kaneshiro K, Motoyama Y, Kuroki R, Yamada M, Nishimura R, Okido M, Oda Y, Nakamura M. Transcription factor T-bet and PD-L1 expression in tumor microenvironment of triple-negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-22.

PD-L1 expression in colorectal cancer defines three subsets of tumor immune microenvironments.

ObjectivesWe investigated the PD-L1 expression in colorectal cancer (CRC) and in its microenvironment.ResultsPD-L1 was expressed in neoplastic cells (NCs) and tumor-infiltrating immune cells (IICs). All samples PD-L1+ on NCs were also on IICs. Three types of cancers could be grouped: group A(NCs-/ IICs-); group B (NCs-/ IICs+); group C (NCs+/IICs+). To group A belong tumors characterized by poorly immunogenic competence, poor immune response but massive granulocyte infiltrate, justifying the absence of PD-L1 as an immunoinhibitor receptor. To Group B probably belong more immunogenic CRCs, justifying the strong IICs-mediated immune response, and up-regulation of PD-L1 expression only on IICs. To group C belong CRCs probably characterized by a large amount of tumor neoantigens resulting in a marked infiltration of lymphocytes and PD-L1 upregulation also in NCs.Materials and MethodsSixty-three colorectal cancer specimens from a cohort of 61 patients were retrospectively reviewed. Thirty-seven MSS and 26 MSI-H CRCs enrolled in this study. Immunohistochemical staining to PD-L1 was performed by using MAb E1L3N.ConclusionsOur study calls attention to the importance to assess PD-L1 expression in tumor microenvironment also evaluating type and density of infiltrating immune cells to better stratify CRCs with different immunological patterns.

Immunoclassification characterized by CD8 and PD-L1 expression is associated with the clinical outcome of gastric cancer patients.

BackgroundGastric cancer (GC) is a major cause of cancer deaths, especially in Eastern Asia. Current classification systems, including the WHO, Lauren, and TCGA, have clarified the pathological and molecular profiles of GC. However, these classifications lack an association with clinical outcome and guidance for medication selection.ObjectiveWe aimed to identify a new immunoclassification for GC to better predict patient prognosis and aid in patient selection for immunotherapy.ResultsFor all samples, 35 were EBV positive (+) and 112 were EBV negative (-). EBV infection was associated with the number of CD3+ T cells (OR = 2.91 95% CI 1.27-6.68, p = 0.012) and PD-L1 expression in TME (OR = 2.57, 95% CI 1.13–5.82, p = 0.024). EBV+ patients showed a poor overall survival (OS) compared with EBV- patients (HR = 2.37; 95% CI, 1.03–5.41; p = 0.011). Importantly, WIR patients lived significantly shorter than SIR patients with high CD8+ T cells and low PD-L1 expression (HR = 3.37; 95% CI, 1.63–6.97; p = 0.015).Materials and Methods147 formalin-fixed and paraffin-embedded (FFPE) samples of GC were obtained. Epstein-Barr virus (EBV) infection was measured. Immune markers including CD3, CD8 and PD-L1 were detected by immunohistochemistry (IHC) at tumor infiltration area (TI) and invasive margin area (IM) in tumor microenvironment (TME). PD-L1 expression was assessed by immunoreactive score (IRS) system. For immunoclassification, patients were classified into two subgroups: strong immunoreaction (SIR) and weak immunoreaction (WIR) defined by the number of CD8+ T cells and PD-L1 expression in TI.ConclusionsIn this study, we suggest a new immunoclassification for gastric cancer which is associated with patient outcome and may provide a way to guide immunotherapy in the future.

Abstract 4567: Immunoclassification of gastric cancer in the context of clinical outcome

Abstract Background: Gastric cancer (GC) plays a leading role in all cancer deaths especially in Eastern Asia. Current classifications including WHO, Lauren, and TCGA defined molecular classification have illuminated the clinicopathological characteristics or genetic profile of GC. However, these classifications were lack of association with clinical outcome and guidance for medication selection. Objective: We aimed to identify a new immunoclassification for GC to predict patient’s prognosis and provide evidence for choosing proper medication. Methods: Formalin-fixed and paraffin-embedded (FFPE) samples of GC were obtained along with the clinical outcome of the patient. Epstein-Barr virus (EBV) infection was measured by RT-PCR. Immune markers including CD3, CD8 and PD-L1 were measured by immunohistochemistry (IHC) at tumor infiltration area (TI) and invasive margin area (IM). The expression of PD-L1 in tumor microenvironment (TME) was assessed by immune reactive score (IRS) system. For immunoclassification, patients were classified into two subgroups: strong immunoreaction (SIR) and weak immunoreaction (WIR) defined by the number of CD8+ T cells and PD-L1 expression at TI. Results: EBV infection was associated with the number of CD3+T cells and PD-L1 expression in TME. EBV+ patients also showed a poor overall survival (OS) compared with EBV- patients. Importantly, WIR patients lived significantly shorter than SIR patients. Moreover, patients who were treated by taxanes in WIR group had a shorter OS compared with those not using taxanes. Conclusion: In this study, we suggest a new immunoclassification for gastric cancer which is associated with patients’ outcome and may provide a way to guide chemotherapy. Citation Format: Weili Wang, Ping Liao, Shangchen Xie, Dongya Shen, Chengfang Zhou, Howard Mcleod, Yijing He. Immunoclassification of gastric cancer in the context of clinical outcome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4567. doi:10.1158/1538-7445.AM2017-4567

Noninvasive Imaging of Immune Checkpoint Ligand PD-L1 in Tumors and Metastases for Guiding Immunotherapy.

Immunotherapy holds great promise in cancer treatment. The challenges in advancing immunotherapies lie in patient stratification and monitoring therapy. Noninvasive detection of immune checkpoint ligand PD-L1 can serve as an important biomarker for guidance and monitoring of immunotherapy. Here in, we provide an overview of our efforts to develop clinically translatable PD-L1-specific imaging agents for quantitative and real-time assessment of PD-L1 expression in tumor microenvironment.