The Prognostic Role of Programmed Death-Ligand 1 in Nasopharyngeal Carcinoma

The predictive role of PD-L1 in head and neck cancer: A systematic review and meta-analysis

This systematic review and meta-analysis investigates the predictive and prognostic role of PD-L1 expression in treating head and neck squamous cell carcinoma (HNSCC). Recognizing the importance of PD-L1 in patient response to treatment, the main objective was to assess its impact on overall survival and progression-free survival in HNSCC patients. A thorough search of databases such as PubMed, Scopus, and Web of Science from 2010 to 2022, along with relevant articles and references, yielded 120 studies. Of these, 7 met the criteria focusing on HNSCC patients, PD-L1 expression evaluation, and treatment with PD-1 or PD-L1 inhibitors. Data extraction followed PRISMA guidelines and involved independent review and consensus for discrepancies. The primary outcomes analyzed were overall survival and progression-free survival in relation to PD-L1 expression levels in patients undergoing immunotherapy.Theseven randomized controlled trials selected had a total of 4,477 participants. Results showed that patients with positive PD-L1 expression experienced improved overall survival when treated with PD-1 or PD-L1 inhibitors, particularly those with high PD-L1 expression. However, PD-L1 expression did not significantly affect progression-free survival. These findings suggest that PD-L1 expression can be a predictive marker for better overall survival in HNSCC patients treated with immunotherapy. However, its influence on progression-free survival remains unclear, indicating the need for further research.

Epstein-Barr Virus BRLF1 Induces PD-L1 Expression in Nasopharyngeal Carcinoma Cells

Nasopharyngeal carcinoma (NPC) is a specific human malignancy with unique geographic distribution and genetic backgrounds. Although early treatment with radio-chemotherapy has been proven effective for NPC therapy, its therapeutic efficacy substantially diminishes in the late stages of this malignancy. In the tumor microenvironment of NPC, PD-L1 has been demonstrated as a critical factor in impairing T cell activation. As an etiological role for NPC development, it is found that Epstein-Barr virus (EBV) latent proteins upregulated PD-L1 expression. However, whether EBV lytic protein affects PD-L1 expression remains unclear. In this study, through monitoring the mRNA expression pattern of lytic genes and PD-L1 in EBV-positive NPC cell line NA, EBV immediately-early gene BRLF1(Rta) was found to have the potential for PD-L1 activation. Furthermore, we identified that Rta expression enhanced PD-L1 expression in mRNA and protein levels through quantitative real-time polymerase chain reaction and western blotting analysis. The luciferase reporter assay revealed that Rta expression enhanced PD-L1 promoter activity. We also demonstrated that Rta-induced PD-L1 expressions could impair interleukin 2 secretion of T cells, and this mechanism may be through ERK activation. These results displayed the importance of EBV Rta in PD-L1 expression in NPC and may give an alternative target for NPC therapy.

TGF-β1-Mediated PD-L1 Glycosylation Contributes to Immune Escape via c-Jun/STT3A Pathway in Nasopharyngeal Carcinoma

Immunotherapy targeting programmed death ligand-1/programmed cell death protein-1 (PD-L1/PD-1) has achieved great success in multiple cancers, but only a small subset of patients showed clinical responses. Recent evidences have shown that post-translational modification of PD-L1 protein could regulate its protein stability and interaction with cognate receptor PD-1, thereby affecting anticancer immunotherapy in several solid tumors. However, the molecular mechanisms underlying how PD-1/PD-L1 expression is regulated still remain unclear in nasopharyngeal carcinoma (NPC). Here, we found N-glycosylation of PD-L1 in NPC cells and tissues. Mechanistically, we showed that STT3A transferred N-linked glycans to PD-L1, and TGF-β1 could positively regulate STT3A expression through activating c-Jun to bind to STT3A promoter. Functional assays showed that inhibition of TGF-β1 resulted in a decrease of glycosylated PD-L1 and enhanced cytotoxic T-cell function against NPC cells. Analysis of clinical specimens revealed that the expression of STT3A was positively correlated with TGF-β1 and c-Jun, and high STT3A expression was positively correlated with a more advanced clinical stage. Altogether, TGF-β1 activated c-Jun/STT3A signaling pathway to promote N-glycosylation of PD-L1, thus further facilitating immune evasion and reducing the efficacy of cancer immunotherapy. As such, all these data suggested that targeting TGF-β1 pathway might be a promising approach to enhance immune checkpoint blockade, and simultaneous blockade of PD-L1 and TGF-β1 pathways might elicit potent and superior antitumor activity relative to monotherapies.

PD-L1 evaluation in head and neck squamous cell carcinoma: Insights regarding specimens, heterogeneity and therapy

Immunohistochemical assessment with combined positive score (CPS) of programmed death-ligand 1 (PD-L1) is the prerequisite for administration of checkpoint inhibitor therapy in head and neck squamous cell carcinoma (HNSCC). Practicing pathologists are required to assess PD-L1 in routinary work and can be faced up with practical issues not always addressed in clinical trials or guidelines, such as choice of specimen to test, the intrinsic heterogeneity in PD-L1 expression in tumors and the potential impact of already administered therapy, given that patients' material can be procured at several times of cancer natural history. In the present work, we review and discuss the recent literature regarding the assessment of PD-L1 in HNSCC from the perspective of the practicing pathologist, providing some evidence on the single issues. It emerges a general trend to an underestimation of PD-L1 expression in biopsies compared to resection specimens and to a higher degree of positivity in metastatic lymph nodes in respect to primary tumors. Moreover, therapy shows to have contrasting effect on PD-L1 expression. Although further studies are needed, taking into account the intrinsic heterogeneity in PD-L1 expression and the conflicting evidences, it may be speculated that the most recent material of patients in respect to the natural history of tumor can be the most reliable to evaluate PD-L1 expression.

PD-L1 Expression is Highly Associated with Tumor-Associated Macrophage Infiltration in Nasopharyngeal Carcinoma

Purpose

Tumour-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment and provide a barrier against the cytotoxic effector functions of T cells and natural killer (NK) cells. Recently, TAMs have become increasingly recognised as an attractive target in combination therapy with PD-1/PD-L1 immuno-checkpoint blockades (ICBs). However, the relationship between PD-L1 expression and TAMs remains unknown in nasopharyngeal carcinoma (NPC).

Patients and Methods

A total of 212 NPC patients from Nanfang hospital were collected in this study. We evaluated the expression of PD-L1 in tumor cells, CD68 (pan-macrophages), and CD163 (M2-like macrophage) in NPC tissues using immunohistochemical (IHC) staining.

Results

The positivity of PD-L1 on tumor cells was 61.3% (130/212). The infiltration densities of CD68+ cells and CD163+ cells in PD-L1-positive NPC tissues were significantly higher than those in PD-L1-negative NPC tissues (P=0.0012 for CD68; P<0.0001 for CD163). Logistic regression analysis showed that high densities of CD68+ macrophages and CD163+ TAMs were significantly associated with increased PD-L1 expression. Subgroup analyses demonstrated that a positive PD-L1 expression on tumor cells in combination with lower CD163+ TAMs density was significantly associated with favorable prognosis, whereas negative PD-L1 expression on tumor cells with higher CD163+ TAMs density was associated with worse prognosis.

Conclusion

The PD-L1 expression in tumor cells was positively correlated with TAMs density in tumor microenvironment of NPC, suggesting TAMs as a new target for combination therapy to improve the response rate of ICBs in NPC treatment.

Prognostic impact of neutrophils-to-lymphocytes ratio (NLR), PD-L1 expression, and tumor immune microenvironment in laryngeal cancer

PURPOSE

In laryngeal carcinoma (LSCC), tumor immune microenvironment is attracting increasing interest, given the recent progresses in immunotherapy. Immune cells migrate to tumors as a result of a tumor antigen-induced immune reaction and cancer cells recruit immune regulatory cells to induce an immunosuppressive network, resulting in the escape from host immunity. This interaction reflects both on tumor microenvironment and systemic inflammatory status. Blood neutrophil-to-lymphocyte ratio (NLR), reflecting a highly pro-inflammatory status, has been related to worse oncological survival outcomes. The aim of this study was to analyze in LSCC the relationship between circulating inflammatory cells (also in terms of NLR) and tumor immune microenvironment histopathological features (programmed cell death ligand 1 [PD-L1] expression, and tumor-infiltrating lymphocytes [TILs]), also investigating their clinical-pathological and prognostic significance.

METHODS

Blood pre-operative NLR, and, at pathology, PD-L1 (in terms of combined positive score [CPS]) and TILs were assessed on 60 consecutive cases of LSCC.

RESULTS

Blood NLR, neutrophils, and lymphocytes counts showed a significant value in predicting DFS and recurrence risk. Moreover, PD-L1 CPS ≥ 1 and TILs count rate ≥30% were associated with higher disease-free survival (DFS) and reduced recurrence risk. A logistic regression model found a significant positive association between increasing NLR values, and PD-L1 CPS < 1 and TILs count rate <30%.

CONCLUSIONS

Further studies are needed to better characterize the role of pre-operative blood NLR in association with PD-L1 expression and tumor immune microenvironment features as prognostic factors and markers of anti-tumor immune response in LSCCs, also with regard to the effectiveness of immunotherapeutic protocols.

PD-L1 and prognosis in patients with malignant pleural mesothelioma: a meta-analysis and bioinformatics study

BACKGROUND

The prognostic value of programmed death-ligand 1 (PD-L1) expression in patients with malignant pleural mesothelioma (MPM) has been controversial according to previous investigations. Therefore, we conducted a meta-analysis to assess the potential prognostic significance of PD-L1 expression in MPM.

METHODS

PubMed, Embase, Web of Science, Scopus, and the Cochrane Library were thoroughly searched for relevant original articles published before 9 April 2020. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) of overall survival (OS) and progression-free survival (PFS) were calculated. The results of the meta-analysis were verified using The Cancer Genome Atlas (TCGA) dataset.

RESULTS

In total 16 studies were included in our meta-analysis. A high PD-L1 expression was associated with a poor OS (HR = 1.53, 95% CI = 1.28-1.83, p < 0.001), but not a grave PFS (HR = 1.07, 95% CI = 0.82-1.39, p = 0.643) in MPM. Furthermore, the PD-L1 expression correlated with the sarcomatoid + biphasic type of MPM (odds ratio = 4.32, 95% CI = 2.16-8.64, p < 0.001). TCGA data indicated that PD-L1 was a significant prognostic factor for OS (HR = 2.069, 95% CI = 1.136-3.769, p = 0.0175), but not for PFS (HR = 1.205, 95% CI = 0.572-2.539, p = 0.624), which was in accordance with the results of the meta-analysis.

CONCLUSION

A high PD-L1 expression is a significant prognostic factor for poor OS of patients with MPM. We therefore suggest that PD-L1 expression levels can be used to predict the clinical outcomes of patients with MPM in the future.

Comparison of whole exome sequencing in circulating tumor cells of primitive and metastatic nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is one of the most common cancers. To investigate the gene mutation profile of NPC patients, we performed whole exome sequencing (WES) in tumor cells, peripheral blood cells, and circulating tumor cells (CTCs) of primitive and metastatic NPC patients, and explored its clinical significance.

METHODS

Primitive tumor cells, white blood cells, and CTCs of patients were collected and hybridized with probes targeting whole exons. Mutational signatures, signaling pathways, and cancer associated genes from CTCs cells of two primitive and two metastatic patients were analyzed using gene ontology (GO) method.

RESULTS

The mutational landscape of four primitive tumors showed that there were more MSH2 alterations in more non-silent mutation number patients Additionally, BAP1 gene mutation only occurred in metastatic patients. The most frequently mutated genes among the primitive tumor and CTC samples were CFAP74, MOB3C, PDE4DIP, IGFN1, CYFIP2, NOP16, SLC22A1, ZNF117, and SSPO. Interestingly, only PMS1, BRIP1, DEE, OR2T12, CPN2, MLXIPL, BAIAP3, IGSF3, SIN3B, and ZNF880 alterations occurred in primary tumors of metastatic patients. Primitive and metastatic NPC had significantly distinct mutational signatures. GO analysis revealed that each patient had his own mutational signaling pathways. Non-silent single nucleotide variations (non-silent SNVs) and insertion-deletion mutations (INDELs) in CTCs were more dramatic than in primitive tumor cells.

CONCLUSIONS

These changes are strongly relevant to their clinical characteristics and therapeutic strategy.

Prognostic role of programmed death ligand 1 (PD-L1) and the immune microenvironment in laryngeal carcinoma

OBJECTIVES

The immune system is crucial in the evolution of head and neck cancer. Programmed cell death ligand 1 (PD-L1) seems to rely on close relations between neoplastic cells and immune cells in the tumor microenvironment. The main aim of this study was to apply univariate/multivariate analysis to investigate the prognostic significance of PD-L1, tumor-infiltrating lymphocytes (TILs), and tertiary lymphoid structures (TLS) in laryngeal carcinoma (LSCC).

MATERIALS AND METHODS

PD-L1 (in terms of combined positive score [CPS]), TILs and TLS were assessed at pathology on 70 consecutive samples of LSCC.

RESULTS

A CPS ≥ 1 coincided with a lower recurrence rate (RR) (p = 0.007) and longer disease-free survival (DFS) than a CPS < 1 (p = 0.0027). Cases with higher TIL counts showed a lower RR (p = 0.036) and longer DFS than those with lower TIL counts (p = 0.0062). Cases revealing TLS had a lower RR (p = 0.004) and longer DFS (p = 0.0034) than those with no TLS. On multivariate analysis, the presence of TLS retained its positive prognostic value (p = 0.024), while CPS remained significant as regards disease recurrence (p = 0.050).

CONCLUSIONS

PD-L1 seems to be an indirect marker of effective anti-tumor response in LSCC, possibly being expressed as a result of a greater immune pressure on cancer cells. The presence of TLS emerged as a positive prognostic factor. Further prospective studies are needed to characterize the role of PD-L1 as a marker of anti-tumor immune response and prognostic factor in LSCC, also with regard to the effectiveness of immunotherapeutic protocols.