Gene Summary

Gene:PDCD1; programmed cell death 1
Aliases: PD1, PD-1, CD279, SLEB2, hPD-1, hPD-l, hSLE1
Summary:This gene encodes a cell surface membrane protein of the immunoglobulin superfamily. This protein is expressed in pro-B-cells and is thought to play a role in their differentiation. In mice, expression of this gene is induced in the thymus when anti-CD3 antibodies are injected and large numbers of thymocytes undergo apoptosis. Mice deficient for this gene bred on a BALB/c background developed dilated cardiomyopathy and died from congestive heart failure. These studies suggest that this gene product may also be important in T cell function and contribute to the prevention of autoimmune diseases. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:programmed cell death protein 1
Source:NCBIAccessed: 07 August, 2020


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1995-2020)
Graph generated 07 August 2020 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 07 August, 2020 using data from PubMed, MeSH and CancerIndex

Specific Cancers (9)

Latest Publications: PDCD1 (cancer-related)

Bao R, Hernandez K, Huang L, Luke JJ
J Immunother Cancer. 2020; 8(2) [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Pandemic COVID-19 by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) infection is facilitated by the ACE2 receptor and protease TMPRSS2. Modestly sized case series have described clinical factors associated with COVID-19, while
METHODS: We performed an integrated study of
RESULTS: Matched normal tissues generally display higher
CONCLUSIONS: We performed a large-scale integration of

Skafi N, Fayyad-Kazan M, Badran B
Immunomodulatory role for MicroRNAs: Regulation of PD-1/PD-L1 and CTLA-4 immune checkpoints expression.
Gene. 2020; 754:144888 [PubMed] Related Publications
The development and progression of different pathologies including, cancer, are associated with suppressed immune responses. This restrained immune activity could be associated with the activation of different immune checkpoint pathways that mediate immunosuppressive functions. Therapeutic Protocols based on abolishing the activity of immune check points provided a promising potential for treating cancer. Among the distinct known immune checkpoints, PD-1/PD-L1 and CTLA-4, are the most studied and have been the focus for development of different blocking agents. Monoclonal antibodies that can block PD-1, PD-L1 or CTLA4 have been approved for treatment of different cancers. MicroRNAs (miRNAs), short non-coding regulatory RNA molecules, could repress mRNA expression at a post-transcriptional level. Many miRNAs have been reported to modulate the expression of CTLA-4 and PD-1/PD-L1, either directly or indirectly, in multiple pathological cases, mainly cancer. In this review, after a brief introduction about T cell activation and immune checkpoints, the miRNAs regulating the expression of CTLA-4 and PD-1/PD-L1 are discussed with highlights on their role in cancer. Many of these miRNAs could serve as novel treatments in different types of cancer as detailed throughout the review.

Zah E, Nam E, Bhuvan V, et al.
Systematically optimized BCMA/CS1 bispecific CAR-T cells robustly control heterogeneous multiple myeloma.
Nat Commun. 2020; 11(1):2283 [PubMed] Free Access to Full Article Related Publications
Chimeric antigen receptor (CAR)-T cell therapy has shown remarkable clinical efficacy against B-cell malignancies, yet marked vulnerability to antigen escape and tumor relapse exists. Here we report the rational design and optimization of bispecific CAR-T cells with robust activity against heterogeneous multiple myeloma (MM) that is resistant to conventional CAR-T cell therapy targeting B-cell maturation antigen (BCMA). We demonstrate that BCMA/CS1 bispecific CAR-T cells exhibit superior CAR expression and function compared to T cells that co-express individual BCMA and CS1 CARs. Combination therapy with anti-PD-1 antibody further accelerates the rate of initial tumor clearance in vivo, while CAR-T cell treatment alone achieves durable tumor-free survival even upon tumor re-challenge. Taken together, the BCMA/CS1 bispecific CAR presents a promising treatment approach to prevent antigen escape in CAR-T cell therapy against MM, and the vertically integrated optimization process can be used to develop robust cell-based therapy against novel disease targets.

Ito S, Masuda T, Noda M, et al.
Prognostic Significance of PD-1, PD-L1 and CD8 Gene Expression Levels in Gastric Cancer.
Oncology. 2020; 98(7):501-511 [PubMed] Related Publications
INTRODUCTION: Anti-programmed cell death 1 (PD-1) therapies have shown promising clinical activity against gastric cancer (GC). We evaluated the clinical significance of immune-related gene expression in GC tissues to better understand the tumor immune microenvironment.
METHODS: PD-1, PD-1 ligand 1 (PD-L1) and CD8 mRNA levels and clinicopathological factors, including survival, were examined by quantitative RT-PCR in 155 GC patients who underwent surgery. PD-1 and PD-L1 expression in tumor tissue from 24 GC patients was investigated by immunohistochemical analysis.
RESULTS: PD-1, PD-L1 and CD8 mRNA levels were significantly lower in tumor tissue than in normal tissue (p < 0.0001, p < 0.05, and p < 0.0001). GC patients with low PD-1, PD-L1 and CD8 mRNA levels had significantly poorer overall survival (OS) than those with high PD-1, PD-L1 and CD8 mRNA levels, respectively (p < 0.001, p < 0.01 and p < 0.05). Low PD-1, PD-L1 and CD8 mRNA levels were more significantly associated with poor prognosis in undifferentiated-type GC patients than in differentiated-type GC patients (PD-1: differentiated p = 0.0071 vs. undifferentiated p = 0.0024; PD-L1: p = 0.6527 vs. p < 0.0001; CD8: p = 0.4465 vs. p < 0.05). Multivariate analysis showed that lymph node metastasis, peritoneal dissemination, distant metastasis, low PD-1 mRNA levels and low CD8 mRNA levels were independent prognostic factors for worse OS (low PD-1 mRNA level: OR 2.16, 95% CI 1.10-4.58, p < 0.05; low CD8 mRNA level: OR 2.55, 95% CI 1.12-6.90, p < 0.05). PD-1 and PD-L1 mRNA levels in immune cells were significantly associated with PD-1 and PD-L1 protein levels (both p < 0.05), respectively.
CONCLUSIONS: PD-1, PD-L1 and CD8 mRNA levels may reflect antitumor immunity in GC, and low PD-1 and CD8 mRNA levels are potential predictive biomarkers for poor prognosis in GC patients who underwent surgery.

Chen HF, Wu LX, Li XF, et al.
PD-L1 expression level in different thymoma stages and thymic carcinoma: a meta-analysis.
Tumori. 2020; 106(4):306-311 [PubMed] Related Publications
BACKGROUND: The immune checkpoint ligand, programmed cell death 1 ligand 1 (PD-L1), is expressed in various tumors and associated with response to drugs that target programmed cell death protein 1. Previous studies have estimated the level of PD-L1 expression among different stages of thymoma and thymic carcinoma to evaluate its potential use as a diagnostic factor; however, its varying expression level has been problematic. We conducted this meta-analysis of published literature to evaluate PD-L1 expression in thymomas and thymic carcinomas.
METHODS: We analyzed 12 studies that included 320 patients with type A/AB/B1 thymoma, 225 patients with type B2/B3 thymoma, and 180 patients with thymic carcinoma.
RESULTS: No difference in PD-L1 expression level was found between the B2/B3 vs C groups (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.26, 1.76;
CONCLUSION: PD-L1 positivity might be a useful factor to differentiate type A/AB/B1 thymoma from type B2/B3 and thymic carcinoma. This result might be valuable for potential anti PD-L1 treatment in thymoma and thymic carcinoma.

Giulia Mantovani, Fragomeni SM, Inzani F, et al.
Molecular pathways in vulvar squamous cell carcinoma: implications for target therapeutic strategies.
J Cancer Res Clin Oncol. 2020; 146(7):1647-1658 [PubMed] Related Publications
BACKGROUND: Additional prognostic factors and personalized therapeutic alternatives for vulvar squamous cell carcinoma (VSCC), especially for advanced stages with poor prognosis, are urgently needed.
OBJECTIVES: To review and assess literature regarding underlying molecular mechanisms of VSCC target therapeutic and prognostic approaches.
METHODS: We performed a narrative literature review from the inception of the database up to January 2020 limited to English language, organizing knowledge in five main fields: extracellular and intracellular cell cycle deregulation, tumor immune microenvironment, tumor angiogenesis and hormones.
RESULTS: EGFR immunohistochemical overexpression/gene amplification, representing early events in VSCC carcinogenesis, have been correlated with a worse prognosis and led to inclusion of erlotinib in cancer guidelines. p16 expression and HPV positivity are linked to a better prognosis, while p53 overexpression is linked to a worse prognosis; thus, biomarkers could help tailoring conventional treatment and follow-up. The implications of PD-L1 positivity in reference to HPV status and prognosis are still not clear, even though pembrolizumab is part of available systemic therapies. The role of tumor angiogenesis emerges through data on microvessel density, immunohistochemical VEGF staining and evaluation of serum VEGF concentrations. Few data exist on hormonal receptor expression, even though hormonal therapy showed great manageability.
CONCLUSIONS: We suggest adding p16, p53 and HPV status to routine hystopathological examination of vulvar biopsies or surgical specimens. Predictive biomarkers for anti-EGFR and anti-PD-1/PD-L1 drugs are needed. Enough preclinical data supporting anti-angiogenic target therapies in clinical trials are existing. Hormonal receptor expression deserves further investigation.

Touat M, Li YY, Boynton AN, et al.
Mechanisms and therapeutic implications of hypermutation in gliomas.
Nature. 2020; 580(7804):517-523 [PubMed] Related Publications
A high tumour mutational burden (hypermutation) is observed in some gliomas

Lee JH, Shklovskaya E, Lim SY, et al.
Transcriptional downregulation of MHC class I and melanoma de- differentiation in resistance to PD-1 inhibition.
Nat Commun. 2020; 11(1):1897 [PubMed] Free Access to Full Article Related Publications
Transcriptomic signatures designed to predict melanoma patient responses to PD-1 blockade have been reported but rarely validated. We now show that intra-patient heterogeneity of tumor responses to PD-1 inhibition limit the predictive performance of these signatures. We reasoned that resistance mechanisms will reflect the tumor microenvironment, and thus we examined PD-1 inhibitor resistance relative to T-cell activity in 94 melanoma tumors collected at baseline and at time of PD-1 inhibitor progression. Tumors were analyzed using RNA sequencing and flow cytometry, and validated functionally. These analyses confirm that major histocompatibility complex (MHC) class I downregulation is a hallmark of resistance to PD-1 inhibitors and is associated with the MITF

Jevtovic A, Pantic J, Jovanovic I, et al.
Interleukin-33 pretreatment promotes metastatic growth of murine melanoma by reducing the cytotoxic capacity of CD8
Cancer Immunol Immunother. 2020; 69(8):1461-1475 [PubMed] Related Publications
Interleukin-33 (IL-33) regulates innate and acquired immune response to pathogens, self-antigens and tumors. IL-33 effects on tumors depend on the dose and mode of administration along with the type of malignancy. We studied the effects of IL-33 on the development of primary and metastatic melanoma induced by B16-F1 cell line in C57BL/6 mice. Intraperitoneally applied IL-33 restricts primary tumor growth. When administered intranasally 3 days prior to the intravenous injection of the tumor cells, IL-33 promoted growth of B16-F1 melanoma metastases, while B16-F10 gave massive metastases independently of IL-33. To mimic natural dissemination, we next used a limited number (5 × 10

Tanaka A, Zhou Y, Ogawa M, et al.
STAT1 as a potential prognosis marker for poor outcomes of early stage colorectal cancer with microsatellite instability.
PLoS One. 2020; 15(4):e0229252 [PubMed] Free Access to Full Article Related Publications
Proteomic analyses indicate that STAT1 protein (signal transducer and activator of transcription 1 or transcription factor ISGF-3 components p91/p84) is upregulated in some colorectal cancers. This study examined 736 colorectal cancer patients for the expression of STAT1 protein in tissue specimens, including 614 early stage patients and 122 advanced stage patients. Tissue microarrays were constructed, and STAT1 expression was examined by immunohistochemistry and scored semi-quantitatively. Among all cases, 9% of cases displayed high levels of cytoplasmic expression of STAT1 and 15% of cases had positive nuclear expression. Based on statistical analyses of a cohort of 559 early stage patients with survival data and no neoadjuvant therapy, we found that high levels of cytoplasmic expression of STAT1 correlated with shorter survival time in early stage colorectal cancer, particularly of the microsatellite instability (MSI) subtype. Additional analysis of a 244-case cohort of colorectal cancers from the Cancer Genome Atlas found that STAT1 gene expression correlated positively with PD-L1 (CD274) and PD-1 (PDCD1) but had no correlation with KRAS or BRAF mutation status. STAT1 expression showed no clear correlation with any of the 4 clinical diagnostic markers of mismatch repair, MLH1, MSH2, MSH6, and PMS2, suggesting its potential as an independent outcome marker for MSI cancers. Our findings suggest that STAT1 may be used as a potential prognostic protein marker for stratifying the outcome risk of early stage MSI colorectal cancer.

de Hosson LD, Takkenkamp TJ, Kats-Ugurlu G, et al.
Neuroendocrine tumours and their microenvironment.
Cancer Immunol Immunother. 2020; 69(8):1449-1459 [PubMed] Free Access to Full Article Related Publications
Tumours can escape the immune system by expressing programmed death-ligand-1 (PD-L1), which allows them to bind to PD-1 on T-cells and avoid recognition by the immune system. Regulatory T-cells (Tregs), indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) also play a role in immune suppression. Knowledge about the interaction of neuroendocrine tumours (NETs) with their immune microenvironment and the role of immunotherapy in patients with NET is scarce. Here, we investigated the immune microenvironment of serotonin-producing (SP) and non-serotonin-producing NETs (NSP-NETs). Tumours of 33 patients with SP-NET and 18 patients with NSP-NET were studied. Immunohistochemical analyses were performed for PD-L1, T-cells, IDO, TDO, mismatch repair proteins (MMRp) and activated fibroblasts. PD-L1 expression was seen in < 1% of tumour and T-cells. T-cells were present in 33% of NETs, varying between 1 and 10% T-cells per high power field. IDO was expressed in tumour cells in 55% of SP-NETs and 22% of NSP-NETs (p = 0.039). TDO was expressed in stromal cells in 64% of SP-NETs and 13% of NSP-NETs (p = 0.001). No tumours had loss of MMRp. TDO-expressing stromal cells also strongly expressed α-SMA and were identified as cancer-associated fibroblasts (CAFs). Factors that are associated with a response to checkpoint inhibitor treatment were absent or only present to a limited extent in the tumour microenvironment of NETs. The expression of IDO and TDO in a substantial part of NETs and the presence of CAFs suggest two mechanisms that could be responsible for the cold immune microenvironment, which should be explored to enhance anti-tumour immunity and clinical responses.

Zong L, Mo S, Yu S, et al.
Expression of the immune checkpoint VISTA in breast cancer.
Cancer Immunol Immunother. 2020; 69(8):1437-1446 [PubMed] Related Publications
V-domain Ig suppressor of T cell activation (VISTA) is a novel immune checkpoint that is an emerging target for cancer immunotherapy. This study aimed to investigate the expression of VISTA and its association with clinicopathologic parameters as well as with the key immune markers including programmed cell death-1 (PD-1) and PD-1 ligand-1 (PD-L1) in invasive ductal carcinoma (IDC) of the breast [corrected]. Immunohistochemistry was used to detect VISTA, PD-1, PD-L1, and CD8 in tissue microarrays from 919 patients with IDC (N = 341 in the exploratory cohort and  = 578 in the validation cohort). VISTA was expressed on the immune cells of 29.1% (267/919) of the samples and on the tumor cells of 8.2% (75/919). VISTA was more frequently expressed in samples that were estrogen receptor-negative, progesterone receptor-negative, human epidermal growth factor receptor 2-positive, poorly differentiated, human epidermal growth factor receptor 2-enriched, and consisting of basal-like tumors. VISTA on immune cells correlated with PD-1, PD-L1, stromal CD8, and tumor-infiltrating lymphocyte expression and was an independent prognostic factor for improved relapse-free and disease-specific survival in patients with estrogen receptor-negative, progesterone receptor-negative, and basal-like IDC. These findings support therapeutic strategies that modulate VISTA expression, perhaps in combination with PD-1/PD-L1 blockade, in human breast cancer immunotherapy.

Goldberg SB, Schalper KA, Gettinger SN, et al.
Pembrolizumab for management of patients with NSCLC and brain metastases: long-term results and biomarker analysis from a non-randomised, open-label, phase 2 trial.
Lancet Oncol. 2020; 21(5):655-663 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: We did a phase 2 trial of pembrolizumab in patients with non-small-cell lung cancer (NSCLC) or melanoma with untreated brain metastases to determine the activity of PD-1 blockade in the CNS. Interim results were previously published, and we now report an updated analysis of the full NSCLC cohort.
METHODS: This was an open-label, phase 2 study of patients from the Yale Cancer Center (CT, USA). Eligible patients were at least 18 years of age with stage IV NSCLC with at least one brain metastasis 5-20 mm in size, not previously treated or progressing after previous radiotherapy, no neurological symptoms or corticosteroid requirement, and Eastern Cooperative Oncology Group performance status less than two. Modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria was used to evaluate CNS disease; systemic disease was not required for participation. Patients were treated with pembrolizumab 10 mg/kg intravenously every 2 weeks. Patients were in two cohorts: cohort 1 was for those with PD-L1 expression of at least 1% and cohort 2 was patients with PD-L1 less than 1% or unevaluable. The primary endpoint was the proportion of patients achieving a brain metastasis response (partial response or complete response, according to mRECIST). All treated patients were analysed for response and safety endpoints. This study is closed to accrual and is registered with ClinicalTrials.gov, NCT02085070.
FINDINGS: Between March 31, 2014, and May 21, 2018, 42 patients were treated. Median follow-up was 8·3 months (IQR 4·5-26·2). 11 (29·7% [95% CI 15·9-47·0]) of 37 patients in cohort 1 had a brain metastasis response. There were no responses in cohort 2. Grade 3-4 adverse events related to treatment included two patients with pneumonitis, and one each with constitutional symptoms, colitis, adrenal insufficiency, hyperglycaemia, and hypokalaemia. Treatment-related serious adverse events occurred in six (14%) of 42 patients and were pneumonitis (n=2), acute kidney injury, colitis, hypokalaemia, and adrenal insufficiency (n=1 each). There were no treatment-related deaths.
INTERPRETATION: Pembrolizumab has activity in brain metastases from NSCLC with PD-L1 expression at least 1% and is safe in selected patients with untreated brain metastases. Further investigation of immunotherapy in patients with CNS disease from NSCLC is warranted.
FUNDING: Merck and the Yale Cancer Center.

Qin G, Wang X, Ye S, et al.
NPM1 upregulates the transcription of PD-L1 and suppresses T cell activity in triple-negative breast cancer.
Nat Commun. 2020; 11(1):1669 [PubMed] Free Access to Full Article Related Publications
Programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) interaction plays a crucial role in tumor-associated immune escape. Here, we verify that triple-negative breast cancer (TNBC) has higher PD-L1 expression than other subtypes. We then discover that nucleophosmin (NPM1) binds to PD-L1 promoter specifically in TNBC cells and activates PD-L1 transcription, thus inhibiting T cell activity in vitro and in vivo. Furthermore, we demonstrate that PARP1 suppresses PD-L1 transcription through its interaction with the nucleic acid binding domain of NPM1, which is required for the binding of NPM1 at PD-L1 promoter. Consistently, the PARP1 inhibitor olaparib elevates PD-L1 expression in TNBC and exerts a better effect with anti-PD-L1 therapy. Together, our research has revealed NPM1 as a transcription regulator of PD-L1 in TNBC, which could lead to potential therapeutic strategies to enhance the efficacy of cancer immunotherapy.

Yu S, Wang Y, Hou J, et al.
Tumor-infiltrating immune cells in hepatocellular carcinoma: Tregs is correlated with poor overall survival.
PLoS One. 2020; 15(4):e0231003 [PubMed] Free Access to Full Article Related Publications
Systematic interrogation of tumor-infiltrating immune cells (TIICs) is key to the prediction of clinical outcome and development of immunotherapies. However, little is known about the TIICs of hepatocellular carcinoma (HCC) and its impact on the prognosis of patients and potential for immunotherapy. We applied CIBERSORT of 1090 tumors to infer the infiltration of 22 subsets of TIICs using gene expression data. Unsupervised clustering analysis by 22 TIICs revealed 4 clusters of tumors, mainly defined by macrophages and T cells, with distinct prognosis and associations with immune checkpoint molecules, including PD-1, CD274, CTLA-4, LAG-3 and IFNG. We found tumors with decreased number of M1 macrophages or increased regulatory T cells were associated with poor prognosis. Based on the multivariate Cox analysis, a nomogram was also established for clinical application. In conclusion, composition of the TIICs in HCC was quite different, which is an important determinant of prognosis with great potential to identify candidates for immunotherapy.

Orth MF, Buecklein VL, Kampmann E, et al.
A comparative view on the expression patterns of PD-L1 and PD-1 in soft tissue sarcomas.
Cancer Immunol Immunother. 2020; 69(7):1353-1362 [PubMed] Related Publications
Soft tissue sarcomas (STSs) are heterogeneous cancers associated with poor prognosis due to high rates of local recurrence and metastasis. The programmed death receptor ligand 1 (PD-L1) is expressed in several cancers. PD-L1 interacts with its receptor, PD-1, on the surface of tumor-infiltrating lymphocytes (TILs), thereby attenuating anti-cancer immune response. Immune checkpoint inhibitors targeting this interaction have been established as effective anti-cancer drugs. However, studies on the PD-L1 and PD-1 expression status in STS are commonly limited by small sample size, analysis of single STS subtypes, or lack of combinatorial marker assessment. To overcome these limitations, we evaluated the expression patterns of intratumoral PD-L1, the number of TILs, their PD-1 expression, and associations with clinicopathological parameters in a large and comprehensive cohort of 225 samples comprising six STS subtypes. We found that nearly all STS subtypes showed PD-L1 expression on the tumor cells, albeit with a broad range of positivity across subtypes (50% angiosarcomas to 3% synovial sarcomas). Co-expression and correlation analyses uncovered that PD-L1 expression was associated with more PD-1-positive TILs (P < 0.001), higher tumor grading (P = 0.016), and worse patients' 5-year overall survival (P = 0.028). The results were in line with several publications on single STS subtypes, especially when comparing findings for STS with low and high mutational burden. In sum, the substantial portion of PD-L1 positivity, the co-occurrence of PD-1-positive TILs, and the association of PD-L1 with unfavorable clinical outcome provide rationales for immune checkpoint inhibition in patients with PD-L1-positive STS.

Guo L, Cao C, Goswami S, et al.
Tumoral PD-1hiCD8+ T cells are partially exhausted and predict favorable outcome in triple-negative breast cancer.
Clin Sci (Lond). 2020; 134(7):711-726 [PubMed] Related Publications
Tumor-infiltrating PD-1hi dysfunctional CD8+ T cells have been identified in several tumors but largely unexplored in breast cancer (BC). Here we aimed to extensively explore PD-1hiCD8+ T cells in BC, focusing on the triple-negative BC (TNBC) subtype. Flow cytometry was used to study the phenotypes and functions of CD8+ T-cell subsets in peripheral blood and surgical specimens from treatment-naive BC patients. RNA-seq expression data generated to dissect the molecular features of tumoral PD-1neg, PD-1lo and PD-1hi CD8+ T cells. Further, the associations between tumoral PD-1hi CD8+ T cells and the clinicopathological features of 503 BC patients were explored. Finally, multiplexed immunohistochemistry (mIHC) was performed to evaluate in situ PD-1hiCD8+ T cells on the tissue microarrays (TMAs, n=328) for prognostic assessment and stratification of TNBC patients. PD-1hiCD8+ T cells found readily detectable in tumor tissues but rarely in peripheral blood. These cells shared the phenotypic and molecular features with exhausted and tissue-resident memory T cells (TRM) with a skewed TCR repertoire involvement. Interestingly, PD-1hiCD8+ T cells are in the state of exhaustion characterized by higher T-BET and reduced EOMES expression. PD-1hiCD8+ T cells found preferentially enriched within solid tumors, but predominant stromal infiltration of PD-1hiCD8+ T subset was associated with improved survival in TNBC patients. Taken together, tumoral PD-1hiCD8+ T-cell subpopulation in BC is partially exhausted, and their abundance signifies 'hot' immune status with favorable outcomes. Reinvigorating this population may provide further therapeutic opportunities in TNBC patients.

Natoli M, Bonito N, Robinson JD, et al.
Human ovarian cancer intrinsic mechanisms regulate lymphocyte activation in response to immune checkpoint blockade.
Cancer Immunol Immunother. 2020; 69(8):1391-1401 [PubMed] Free Access to Full Article Related Publications
Immune checkpoint blocking antibodies are currently being tested in ovarian cancer (OC) patients and have shown some responses in early clinical trials. However, it remains unclear how human OC cancer cells regulate lymphocyte activation in response to therapy. In this study, we have established and optimised an in vitro tumour-immune co-culture system (TICS), which is specifically designed to quantify the activation of multiple primary human lymphocyte subsets and human cancer cell killing in response to PD-1/L1 blockade. Human OC cell lines and treatment naïve patient ascites show differential effects on lymphocyte activation and respond differently to PD-1 blocking antibody nivolumab in TICS. Using paired OC cell lines established prior to and after chemotherapy relapse, our data reveal that the resistant cells express low levels of HLA and respond poorly to nivolumab, relative to the treatment naïve cells. In accordance, knockdown of IFNγ receptor expression compromises response to nivolumab in the treatment naïve OC cell line, while enhanced HLA expression induced by a DNA methyltransferase inhibitor promotes lymphocyte activation in TICS. Altogether, our results suggest a 'cross resistance' model, where the acquired chemotherapy resistance in cancer cells may confer resistance to immune checkpoint blockade therapy through down-regulation of antigen presentation machinery. As such, agents that can restore HLA expression may be a suitable combination partner for immunotherapy in chemotherapy-relapsed human ovarian cancer patients.

von Roemeling CA, Wang Y, Qie Y, et al.
Therapeutic modulation of phagocytosis in glioblastoma can activate both innate and adaptive antitumour immunity.
Nat Commun. 2020; 11(1):1508 [PubMed] Free Access to Full Article Related Publications
Tumour cell phagocytosis by antigen presenting cells (APCs) is critical to the generation of antitumour immunity. However, cancer cells can evade phagocytosis by upregulating anti-phagocytosis molecule CD47. Here, we show that CD47 blockade alone is inefficient in stimulating glioma cell phagocytosis. However, combining CD47 blockade with temozolomide results in a significant pro-phagocytosis effect due to the latter's ability to induce endoplasmic reticulum stress response. Increased tumour cell phagocytosis subsequently enhances antigen cross-presentation and activation of cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) in APCs, resulting in more efficient T cell priming. This bridging of innate and adaptive responses inhibits glioma growth, but also activates immune checkpoint. Sequential administration of an anti-PD1 antibody overcomes this potential adaptive resistance. Together, these findings reveal a dynamic relationship between innate and adaptive immune regulation in tumours and support further investigation of phagocytosis modulation as a strategy to enhance cancer immunotherapy responses.

Färkkilä A, Gulhan DC, Casado J, et al.
Immunogenomic profiling determines responses to combined PARP and PD-1 inhibition in ovarian cancer.
Nat Commun. 2020; 11(1):1459 [PubMed] Free Access to Full Article Related Publications
Combined PARP and immune checkpoint inhibition has yielded encouraging results in ovarian cancer, but predictive biomarkers are lacking. We performed immunogenomic profiling and highly multiplexed single-cell imaging on tumor samples from patients enrolled in a Phase I/II trial of niraparib and pembrolizumab in ovarian cancer (NCT02657889). We identify two determinants of response; mutational signature 3 reflecting defective homologous recombination DNA repair, and positive immune score as a surrogate of interferon-primed exhausted CD8 + T-cells in the tumor microenvironment. Presence of one or both features associates with an improved outcome while concurrent absence yields no responses. Single-cell spatial analysis reveals prominent interactions of exhausted CD8 + T-cells and PD-L1 + macrophages and PD-L1 + tumor cells as mechanistic determinants of response. Furthermore, spatial analysis of two extreme responders shows differential clustering of exhausted CD8 + T-cells with PD-L1 + macrophages in the first, and exhausted CD8 + T-cells with cancer cells harboring genomic PD-L1 and PD-L2 amplification in the second.

Wang X, Yang X, Zhang C, et al.
Tumor cell-intrinsic PD-1 receptor is a tumor suppressor and mediates resistance to PD-1 blockade therapy.
Proc Natl Acad Sci U S A. 2020; 117(12):6640-6650 [PubMed] Article available free on PMC after 11/09/2020 Related Publications
The programmed cell death 1 (PD-1) receptor on the surface of immune cells is an immune checkpoint molecule that mediates the immune escape of tumor cells. Consequently, antibodies targeting PD-1 have shown efficacy in enhancing the antitumor activity of T cells in some types of cancers. However, the potential effects of PD-1 on tumor cells remain largely unknown. Here, we show that PD-1 is expressed across a broad range of tumor cells. The silencing of PD-1 or its ligand, PD-1 ligand 1 (PD-L1), promotes cell proliferation and colony formation in vitro and tumor growth in vivo. Conversely, overexpression of PD-1 or PD-L1 inhibits tumor cell proliferation and colony formation. Moreover, blocking antibodies targeting PD-1 or PD-L1 promote tumor growth in cell cultures and xenografts. Mechanistically, the coordination of PD-1 and PD-L1 activates its major downstream signaling pathways including the AKT and ERK1/2 pathways, thus enhancing tumor cell growth. This study demonstrates that PD-1/PD-L1 is a potential tumor suppressor and potentially regulates the response to anti-PD-1/PD-L1 treatments, thus representing a potential biomarker for the optimal cancer immunotherapeutic treatment.

Christenson ES, Jaffee E, Azad NS
Current and emerging therapies for patients with advanced pancreatic ductal adenocarcinoma: a bright future.
Lancet Oncol. 2020; 21(3):e135-e145 [PubMed] Related Publications
Pancreatic ductal adenocarcinoma is the seventh leading cause of cancer death worldwide with an estimated 432 242 deaths occurring in 2018. This estimate, in conjunction with the findings that pancreatic ductal adenocarcinoma incidence is rising and that pancreatic ductal adenocarcinoma has the highest case-fatality rate of any solid tumour, highlights the urgency for designing novel therapeutic strategies to combat this deadly disease. Through the efforts of the global research community, our knowledge of the factors that lead to the development of pancreatic ductal adenocarcinoma, its progression, and the interplay between tumour cells and their surrounding microenvironment have improved substantially. Although these scientific advances have not yet translated into targeted or immunotherapy strategies that are effective for most patients with pancreatic ductal adenocarcinoma, important incremental progress has been made particularly for the treatment of specific molecular subgroups of tumours. Although PD-1 inhibitors for mismatch-repair-deficient tumours and NTRK inhibitors for tumours containing NTRK gene fusions are the most recent targeted agents approved by the US Food and Drug Administration, olaparib for germline BRCA-mutated pancreatic ductal adenocarcinoma is expected to be approved soon in the maintenance setting. These recent advances show the accelerated pace at which pancreatic ductal adenocarcinoma drugs are achieving successful clinical outcomes. Here we review the current understanding of the pathophysiology of pancreatic ductal adenocarcinoma, recent advances in the understanding of the stromal microenvironment, current standard-of-care treatment, and novel therapeutic targets and strategies that hold promise for improving patient outcomes. We predict that there will be major breakthroughs in the treatment of pancreatic ductal adenocarcinoma in the next 5-10 years. These breakthroughs will result from the increased understanding of the treatment barriers imposed by the tumour-associated stroma, and from the development of novel approaches to re-engineer the tumour microenvironment in favour of effective anticancer responses.

Su L, Guo W, Lou L, et al.
EGFR-ERK pathway regulates CSN6 to contribute to PD-L1 expression in glioblastoma.
Mol Carcinog. 2020; 59(5):520-532 [PubMed] Related Publications
Glioblastoma (GBM) is the most common and malignant brain tumor in adults. Recently, programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) checkpoint blockades have been applied for GBM treatment. However, the mechanism of PD-L1 upregulation in GBM is still unclear. COP9 signalosome 6 (CSN6) is crucial for maintaining the protein stabilization in cancer cells. In this study, we applied human GBM specimens and cell lines to investigate whether the EGFR-ERK pathway regulates CSN6 for PD-L1 upregulation. Data from The Cancer Genome Atlas dataset showed that high expression of EGFR, CSN6, and PD-L1 in patients with glioma was associated with poor prognosis. In 47 human GBM specimens, high expression of PD-L1 was associated with low amount of CD8

Maestre L, García-García JF, Jiménez S, et al.
High-mobility group box (TOX) antibody a useful tool for the identification of B and T cell subpopulations.
PLoS One. 2020; 15(2):e0229743 [PubMed] Article available free on PMC after 11/09/2020 Related Publications
Thymocyte selection-associated high-mobility group box (TOX) is a DNA-binding factor that is able to regulate transcription by modifying local chromatin structure and modulating the formation of multi-protein complexes. TOX has multiple roles in the development of the adaptive immune system including development of CD4 T cells, NK cells and lymph node organogenesis. However very few antibodies recognizing this molecule have been reported and no extensive study of the expression of TOX in reactive and neoplastic lymphoid tissue has been performed to date. In the present study, we have investigated TOX expression in normal and neoplastic lymphoid tissues using a novel rat monoclonal antibody that recognizes its target molecule in paraffin-embedded tissue sections. A large series of normal tissues and B- and T-cell lymphomas was studied, using whole sections and tissue microarrays. We found that the majority of precursor B/T lymphoblastic, follicular and diffuse large B-cell lymphomas, nodular lymphocyte-predominant Hodgkin lymphomas and angioimmunoblastic T-cell lymphomas strongly expressed the TOX protein. Burkitt and mantle cell lymphomas showed TOX expression in a small percentage of cases. TOX was not found in the majority of chronic lymphocytic leukemia, myelomas, marginal zone lymphomas and classical Hodgkin lymphomas. In conclusion, we describe for the first time the expression of TOX in normal and neoplastic lymphoid tissues. The co-expression of TOX and PD-1 identified in normal and neoplastic T cells is consistent with recent studies identifying TOX as a critical regulator of T-cell exhaustion and a potential immunotherapy target. Its differential expression may be of diagnostic relevance in the differential diagnosis of follicular lymphoma, the identification of the phenotype of diffuse large B-cell lymphoma and the recognition of peripheral T-cell lymphoma with a follicular helper T phenotype.

Wu TD, Madireddi S, de Almeida PE, et al.
Peripheral T cell expansion predicts tumour infiltration and clinical response.
Nature. 2020; 579(7798):274-278 [PubMed] Related Publications
Despite the resounding clinical success in cancer treatment of antibodies that block the interaction of PD1 with its ligand PDL1

Zhou YJ, Zhu GQ, Lu XF, et al.
Identification and validation of tumour microenvironment-based immune molecular subgroups for gastric cancer: immunotherapeutic implications.
Cancer Immunol Immunother. 2020; 69(6):1057-1069 [PubMed] Related Publications
BACKGROUND: Immunotherapy could trigger durable response in advanced gastric cancer, but it only benefits a minority of patients. We aimed to propose a robust molecular classification of gastric cancer microenvironment to identify ideal candidates for tailoring effective immunotherapy.
METHODS: A training cohort of 375 gastric cancer samples with RNA sequencing data was analysed. We virtually microdissected tumour, stromal, and immune cell gene expression patterns employing a non-negative matrix factorization algorithm. These expression patterns were annotated using immune- and stromal-related gene signatures. Validation of immunogenomic classification was performed across six microarray datasets of 1406 samples.
RESULTS: We found approximately half of gastric cancer samples to have higher immune cell infiltrates, PD-L1 expression, markers of cytolytic activity, and fewer copy number aberrations (all P < 0.05). We termed this group of tumours the Immune Class, which incorporated two components, namely Immune Activation and Immunosuppressive Subtype, according to immunosuppressive or activated microenvironment. Immune Activation Subtype was associated with improved survival in multivariate survival analysis and shared similar genomic characteristics with responders of anti-PD-1 therapy. Immunosuppressive Subtype featured high immune infiltration, stromal enrichment, and transforming growth factor (TGF)-β signalling pathway activation and correlated with non-responsiveness signature of checkpoint blockade therapy, which might be suitable for anti-PD-L1 and anti-TGF-β combined therapy.
CONCLUSIONS: We proposed and independently validated three reproducible immune molecular subtypes of gastric cancer, which may provide implications for patient selection of immunotherapy.

Wang QT, Nie Y, Sun SN, et al.
Tumor-associated antigen-based personalized dendritic cell vaccine in solid tumor patients.
Cancer Immunol Immunother. 2020; 69(7):1375-1387 [PubMed] Related Publications
Tumor-associated antigens (TAAs) have been tested in various clinical trials in cancer treatment but the patterns of specific T cell response to personalized TAA immunization remains to be fully understood. We report antigen-specific T cell responses in patients immunized with dendritic cell vaccines pulsed with personalized TAA panels. Tumor samples from patients were first analyzed to identify overexpressed TAAs. Autologous DCs were then transfected with pre-manufactured mRNAs encoding the full-length TAAs, overexpressed in the patients' tumors. Patients with glioblastoma multiforme (GBM) or advanced lung cancer received DC vaccines transfected with personalized TAA panels, in combination with low-dose cyclophosphamide, poly I:C, imiquimod and anti-PD-1 antibody. Antigen-specific T cell responses were measured. Safety and efficacy were evaluated. A total of ten patients were treated with DC vaccines transfected with personalized TAA panels containing 3-13 different TAAs. Among the seven patients tested for anti-TAA T cell responses, most of the TAAs induced antigen-specific CD4

Bastaki S, Irandoust M, Ahmadi A, et al.
PD-L1/PD-1 axis as a potent therapeutic target in breast cancer.
Life Sci. 2020; 247:117437 [PubMed] Related Publications
Although both the incidence and the mortality rate of breast cancer is rising, there is no potent and practical option for the treatment of these patients, particularly in advanced stages. One of the most critical challenges for treatment is the presence of complicated and extensive tumor escape mechanisms in the tumor microenvironment. Immune checkpoint molecules are of the main immunosuppressive mechanisms used by cancerous cells to block anti-cancer immune responses. Among these molecules, PD-1 (Programmed cell death) and PD-L1 (programmed cell death-ligand 1) have been considered as worthy therapeutic targets for breast cancer therapy. In this review, we intend to discuss the immunobiology and signaling of the PD-1/PD-L1 axis and highlight its importance as a worthy therapeutic target in breast cancer. We believe that the prognostic value of PD-L1 depends on the breast cancer subtype. Moreover, the combination of PD-1/PD-L1 targeting with immune-stimulating vaccines can be considered as an effective therapeutic strategy in breast cancer.

Sharma S, Kadam P, Dubinett S
CCL21 Programs Immune Activity in Tumor Microenvironment.
Adv Exp Med Biol. 2020; 1231:67-78 [PubMed] Related Publications
CCL21 promotes immune activity in the tumor microenvironment (TME) by colocalizing dendritic cells (DC) and T cells programing ectopic lymph node architectural structures that correlate with cancer prognosis. Innovative strategies to deliver CCL21 in cancer patients will reactivate the downregulated immune activity in the TME. Immune escape mechanisms are upregulated in the TME that promote tumor immune evasion. CCL21 combined with inhibition of dominant pathways of immune evasion will aid in the development of effective immunotherapy for cancer.

Hurkmans DP, Kuipers ME, Smit J, et al.
Tumor mutational load, CD8
Cancer Immunol Immunother. 2020; 69(5):771-777 [PubMed] Article available free on PMC after 11/09/2020 Related Publications
OBJECTIVES: A minority of NSCLC patients benefit from anti-PD1 immune checkpoint inhibitors. A rational combination of biomarkers is needed. The objective was to determine the predictive value of tumor mutational load (TML), CD8
MATERIALS AND METHODS: Metastatic NSCLC patients were prospectively included in an immune-monitoring trial (NTR7015) between April 2016-August 2017, retrospectively analyzed in FFPE tissue for TML (NGS: 409 cancer-related-genes) and by IHC staining to score PD-L1, CD8
RESULTS: 30 patients with adenocarcinoma (67%) or squamous cell carcinoma (33%) were included. High TML was associated with better PFS (p = 0.004) and OS (p = 0.025). Interaction analyses revealed that patients with both high TML and high total CD8
CONCLUSION: This proof-of-concept study suggests that a combination of PD-L1 expression, TML, CD8

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