Polymorphism of the programmed death-ligand 1 gene is associated with its protein expression and prognosis in gastric cancer

Study of immunosenescence in the occurrence and immunotherapy of gastrointestinal malignancies

In human beings heterogenous, pervasive and lethal malignancies of different parts of the gastrointestinal (GI) tract viz., tumours of the oesophagus, stomach, small intestine, colon, and rectum, represent gastrointestinal malignancies. Primary treatment modality for gastric cancer includes chemotherapy, surgical interventions, radiotherapy, monoclonal antibodies and inhibitors of angiogenesis. However, there is a need to improve upon the existing treatment modality due to associated adverse events and the development of resistance towards treatment. Additionally, age has been found to contribute to increasing the incidence of tumours due to immunosenescence-associated immunosuppression. Immunosenescence is the natural process of ageing, wherein immune cells as well as organs begin to deteriorate resulting in a dysfunctional or malfunctioning immune system. Accretion of senescent cells in immunosenescence results in the creation of a persistent inflammatory environment or inflammaging, marked with elevated expression of pro-inflammatory and immunosuppressive cytokines and chemokines. Perturbation in the T-cell pools and persistent stimulation by the antigens facilitate premature senility of the immune cells, and senile immune cells exacerbate inflammaging conditions and the inefficiency of the immune system to identify the tumour antigen. Collectively, these conditions contribute positively towards tumour generation, growth and eventually proliferation. Thus, activating the immune cells to distinguish the tumour cells from normal cells and invade them seems to be a logical strategy for the treatment of cancer. Consequently, various approaches to immunotherapy, viz., programmed death ligand-1 (PD-1) inhibitors, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors etc are being extensively evaluated for their efficiency in gastric cancer. In fact, PD-1 inhibitors have been sanctioned as late late-line therapy modality for gastric cancer. The present review will focus on deciphering the link between the immune system and gastric cancer, and the alterations in the immune system that incur during the development of gastrointestinal malignancies. Also, the mechanism of evasion by tumour cells and immune checkpoints involved along with different approaches of immunotherapy being evaluated in different clinical trials will be discussed.

CD274 (PD-L1) Polymorphisms as Predictors of Efficacy in First-Line Platinum-Based Chemotherapy for Extensive-Stage Small Cell Lung Cancer

The cornerstone of first-line treatment in extensive-stage small cell lung cancer (ES-SCLC) is platinum- and etoposide-based chemotherapy. Platinum compounds could immunomodulate the tumor microenvironment in addition to their cytotoxic effect. Genetic variation in immune checkpoint (IC) pathways may predict chemotherapy efficacy. Polymorphisms in the IC genes were determined, and their association with survival was analyzed in 78 patients with ES-SCLC treated with chemotherapy. PD-L1 protein expression in tumor tissue was determined. Three variants in CD274 were associated with better median progression-free survival (mPFS): rs2297136 (hazard ratio [HR] 0.52, 95% CI 0.29-0.93; p = 0.03), rs2282055 (HR 0.23, 95% CI 0.09-0.64; p = 0.005), and rs822336 (HR 0.41, 95% CI 0.23-0.73; p = 0.002). CTLA4 rs231775 was also associated with mPFS (HR 0.30, 95% CI 0.14-0.63; p = 0.002). The variants CD274 rs2297136 and CD274 rs822336 were associated with platinum sensitivity (odds ratio [OR] 0.13, 95% CI 0.02-0.70; p = 0.02, and OR 0.08, 95% CI 0.01-0.46; p = 0.005, respectively). CD274 rs2297136 was also associated with better overall survival (p = 0.02), but not after adjustment for covariates. No association was found between CD274 germline variants and PD-L1 tumor expression. Our results suggest that CD274 and CTLA4 variants may be predictive biomarkers for platinum plus etoposide treatment in ES-SCLC.

Germline PDCDL1 Gene Variants Are Associated with Increased Primary Melanoma Thickness

Background: The incidence of malignant melanoma (MM) continues to increase annually, and tumour invasiveness is a main prognostic factor. Single-nucleotide polymorphisms (SNPs) have become key tools in the study of cancer genetics, influencing susceptibility and prognosis. Methods: In the present study, we analysed the relationship between five SNPs on the PDCDL1 gene (rs822336, rs822337, rs822338, rs229736, rs4143815) with prognosis as well as primary tumour invasiveness characteristics in 377 whole blood samples from MM individuals. Results: Patients who presented the rs822336 CG or GG genotypes (OR = 3.01, 95% CI = 1.53-5.92; p = 0.0017), TA or TT in rs822337 (OR = 2.45, 95% CI = 1.22-4.93; p = 0.0098), and CT or CC of rs822338 (OR = 2.23, 95% CI = 1.05-4.73; p = 0.028) were at an increased risk of developing invasive melanomas. Cases with the AG or GG genotype in rs2297136 presented a lower risk (OR = 0.29, 95% CI = 0.11-0.75; p = 0.0038) of invasive MM. The genetic analysis at the haplotype level resulted in similar findings (OR: 2.95, 95% CI: 1.08-8.10), p = 0.036). Furthermore, patients carrying the homozygous AA genotype in rs2297136 had thicker tumours than those harbouring the AG or GG (1.4 mm vs. 1.0 and 0.8 mm; p = 0.030). No significant association was found between the studied SNPs and melanoma-specific survival (MSS) nor progression-free survival (PFS). Conclusions: Current results suggest that SNPs rs822336, rs822337, rs822338, and rs2297136 genotypes in the PDCDL1 gene are associated with the risk of tumour invasiveness and tumour thickness in MM. Further studies on SNPs considering genetic and epigenetic factors are needed for a better understanding of malignant melanoma susceptibility and its prognosis.

Determinants of gastric cancer immune escape identified from non-coding immune-landscape quantitative trait loci

The landscape of non-coding mutations in cancer progression and immune evasion is largely unexplored. Here, we identify transcrptome-wide somatic and germline 3' untranslated region (3'-UTR) variants from 375 gastric cancer patients from The Cancer Genome Atlas. By performing gene expression quantitative trait loci (eQTL) and immune landscape QTL (ilQTL) analysis, we discover 3'-UTR variants with cis effects on expression and immune landscape phenotypes, such as immune cell infiltration and T cell receptor diversity. Using a massively parallel reporter assay, we distinguish between causal and correlative effects of 3'-UTR eQTLs in immune-related genes. Our approach identifies numerous 3'-UTR eQTLs and ilQTLs, providing a unique resource for the identification of immunotherapeutic targets and biomarkers. A prioritized ilQTL variant signature predicts response to immunotherapy better than standard-of-care PD-L1 expression in independent patient cohorts, showcasing the untapped potential of non-coding mutations in cancer.

MiRNA polymorphisms affect the prognosis of gastric cancer: insights from Xianyou, Fujian

Introduction

Gastric cancer, characterized by high incidence and substantial disease burden, has drawn continuous attention regarding its occurrence and prognosis. Genetics plays a crucial role in influencing the prognosis of gastric cancer, and single nucleotide polymorphisms are closely associated with the occurrence, development, and prognosis of this malignant tumor. Our study aims to conduct survival analysis on patients carrying different single nucleotide polymorphisms, exploring the relationship between miRNA single nucleotide polymorphisms and the prognosis of gastric cancer.

Methods

Genetic data from 344 patients in Xianyou, Fujian, formed the basis of our study. We delineated the survival rate and median survival time, utilizing the log-rank test and COX regression analysis as statistical tools.

Results

Upon stratifying the data by sex or operation, it was discerned that the GG genotype at MSH2 rs17502941 independently posed a heightened risk for gastric cancer. Other stratification analyses suggested that the subsequent single nucleotide polymorphisms were correlated with patient prognosis: rs17502941, rs884225, rs1468063, rs7143252, and rs2271738.

Discussion

The outcomes of this study strongly suggest that miRNA polymorphisms significantly influence the survival time of gastric cancer patients and can serve as effective predictors for the prognosis of gastric cancer.

Impact of PD-L1 Gene Polymorphisms and Interactions with Cooking with Solid Fuel Exposure on Tuberculosis

INTRODUCTION

Given that PD-L1 is a crucial immune checkpoint in regulating T-cell responses, the aim of this study was to explore the impact of PD-L1 gene polymorphisms and the interaction with cooking with solid fuel on susceptibility to tuberculosis (TB) in Chinese Han populations.

METHODS

A total of 503 TB patients and 494 healthy controls were enrolled in this case-control study. Mass spectrometry technology was applied to genotype rs2297136 and rs4143815 of PD-L1 genes. The associations between single nucleotide polymorphism (SNPs) and TB were assessed using unconditional logistic regression analysis. Marginal structural linear odds models were used to estimate the gene-environment interactions.

RESULTS

Compared with genotype CC, genotypes GG and CG+GG at rs4143815 locus were significantly associated with susceptibility to TB (OR: 3.074 and 1.506, respectively, p < 0.05). However, no statistical association was found between rs2297136 SNP and TB risk. Moreover, the relative excess risk of interaction between rs4143815 of the PD-L1 gene and cooking with solid fuel was 2.365 (95% CI: 1.922-2.809), suggesting positive interactions with TB susceptibility.

CONCLUSION

The rs4143815 polymorphism of the PD-L1 gene was associated with susceptibility to TB in Chinese Han populations. There were significantly positive interactions between rs4143815 and cooking with solid fuel.

The blockage signal for PD-L1/CD274 gene variants and their potential impact on lung carcinoma susceptibility

BACKGROUND

The programmed death-ligand 1 (PD-L1/CD274) gene plays a key function in suppressing anti-tumor immunity through binding to its receptor PD-1 on stimulated T lymphocytes. However, robust associations among diverse populations and lung susceptibility remain unclear. The tentative purpose of this research is to investigate whether PD-L1/CD274 polymorphisms modulate susceptibility to lung carcinoma using totalitarian techniques, including genetic analysis, and sophisticated bioinformatic methods.

METHODS

PD-L1/CD274 (rs822336, rs2297136, and rs4143815) variants were genotyped in 126 lung carcinoma cases and 117 healthy controls using tetra-primer ARMS-PCR. Logistic regression and bioinformatics analyses assessed genetic associations.

RESULTS

The rs2297136 GA genotype significantly increased lung cancer risk by 3.7-fold versus GG genotype (OR 3.69, 95 % CI 1.39-9.81, p = 0.016), with the minor A allele also increasing risk (OR 1.47, p = 0.044). In contrast, the rs4143815 CC genotype was associated with 70 % decreased cancer risk versus GG (OR 0.30, 95 % CI 0.11-0.87, p = 0.012), although the minor C allele itself was not significant. The rs822336 variant showed no association. Haplotype and multivariate analyses supported these findings. In silico predictions suggested functional impacts on PD-L1 expression and activity.

CONCLUSIONS

This study identified novel associations between PD-L1/CD274 polymorphisms and susceptibility to lung cancer in Egyptians. The rs2297136 variant increased risk while the rs4143815 variant conferred protection, highlighting the PD-1/PD-L1 axis as a potential biomarker and therapeutic target in lung oncogenesis. Replication in larger cohorts and functional studies are warranted.

Common inherited variants of PDCD1, CD274 and HAVCR2 genes differentially modulate the risk and prognosis of adenocarcinoma and squamous cell carcinoma

BACKGROUND

To investigate the association between single nucleotide polymorphisms (SNPs) of PDCD1, CD274, and HAVCR2 genes with the risk and outcomes of non-small cell lung cancer (NSCLC) subtypes: squamous cell lung cancer (LUSC) and lung adenocarcinoma (LUAD).

METHODS

TaqMan SNP genotyping assays or polymerase chain reaction-restriction fragment length polymorphism methods were used to determine genotypes of: PDCD1: rs36084323, rs7421861, rs11568821, rs2227981, rs10204525; CD274: rs822335, rs10815225, rs17718883, rs2297136, rs4742098, rs4143815; HAVCR2: rs10057302, rs1036199. Among 383 NSCLC patients, 112 were diagnosed with LUAD and 116 with LUSC. The control group consisted of 433 unrelated, cancer-free subjects.

RESULTS

A CC genotype of rs4143815 and GG genotype of rs4742098 were associated with two times higher risk of developing LUSC (CC vs. GG + GC, OR = 2.31; 95% CI = 1.32, 4.06; P = 0.003; GG vs. AA + AG, OR = 2.26; 95% CI = 1.17, 4.36; P = 0.016, respectively). Moreover, rs4143815 was an independent predictor of the age at diagnosis of LUAD. The carriers of C allele were diagnosed 4.81 years later (95% CI = 1.47, 8.15; P = 0.006) than patients with the GG genotype. The rs10057302 CA genotype was an independent predictor of overall survival in LUSC (adjusted HR = 0.13; 95% CI = 0.02, 0.93; P = 0.043). NSCLC carriers of rs11568821 T allele had almost double the risk of death (adjusted HR = 2.05; 95% CI = 1.28, 3.29; P = 0.003) compared to carriers of CC genotype.

CONCLUSIONS

Our results provided additional evidence that SNPs of genes for PD-1, PD-L1 and TIM-3 differentially modulate the risk and prognosis of LUSC and LUAD.

Non-invasive plasma testing for CD274 UTR structural variations by next-generation sequencing in cancer

Immunotherapy is now the main choice of systemic therapy for many cancer patients, while current biomarkers for tumor immunotherapy may be limited by the accessibility of patient tumor tissue or tumor neoplastic content. Rare mutation in the 5' and 3'-untranslated region (UTR) of CD274 gene (Protein name: PD-L1) has been recently reported in hematologic and solid tumors as a potential biomarker for assessing efficacy during immunotherapy. However, multi-omics analysis for CD274 UTR region, especially circulating tumor DNA (ctDNA), have been little explored in the pan-cancer perspective. We developed a cSMART2.0 technology featured with higher capture efficiency and homogeneity to detect this rare structural variant in 2249 Chinese patients' cohort with multiple cancers. An incidence of 0.36% was detected in this cohort, consistent with TCGA (The Cancer Genome Atlas), while the prevalence of SV in CD274 UTR region in liver and breast cancer were significantly higher than TCGA. The liquid biopsy result from ctDNA was 100% concordance with gDNA result getting from tumor tissue detection, and further validated by immunohistochemistry (IHC) and multiplex immunofluorescence (mIF) experiments. Patients carrying this SV in CD274 UTR region without driver gene mutation responded to immune checkpoint inhibitors (ICIs). This study proves that rare structural variants in CD274 UTR region exist in various cancer in Chinese population for the first time, which can induce immune escape and be used for prediction of response to ICIs. Liquid biopsy based cSMART 2.0 technology could offer more sensitive and accurate detection to navigate potential ICIs patients and to benefit patients with advanced disease when tissue samples are not available.

Programmed death-ligand 1 (PD-L1) polymorphisms as predictive biomarkers for the development of liver cirrhosis and hepatocellular carcinoma in HCV Egyptian patients

BACKGROUND

Considering the immune evasion role of programmed death-ligand 1 (PD-L1) in cancer development, its genomic variations might be closely associated with disease development and cancer risks. Accordingly, this study was performed to investigate how the PD-L1 gene polymorphisms affect the susceptibility to hepatitis C virus (HCV)-induced liver cirrhosis and cancer development in the Egyptian population.

METHODOLOGY

Two single nucleotide polymorphisms of the PD-L1 gene; rs2297136 (A > G) and rs4143815 (C > G), were studied in 50 HCV, 51 liver cirrhosis, and 52 hepatocellular carcinoma (HCC) patients as well as 50 healthy subjects using real-time PCR.

RESULTS

The frequencies of PD-L1 rs2297136 AA and rs4143815 GG genotypes were significantly higher in the liver cirrhosis than the control and HCV groups. The rs4143815 CG and GG genotypes were linked to a higher risk of developing HCC and were positively associated with the clinicopathological features of HCC.

CONCLUSIONS

The PD-L1 rs2297136 AA and rs4143815 GG genotypes increase the susceptibility to liver cirrhosis. The rs4143815 CG and GG genotypes are positively associated with HCC risk and its clinicopathological characteristics. Therefore, HCV patients carrying the PD-L1 rs4143815 G-allele should be followed up on a regular basis to allow for early HCC management.

PD-L1 Gene Polymorphisms rs822336 G>C and rs822337 T>A: Promising Prognostic Markers in Triple Negative Breast Cancer Patients

Background and Objectives: Triple-negative breast cancer (TNBC) is a highly heterogeneous subtype that is associated with unresponsiveness to therapy and hence with high mortality rates. In this study we aimed to investigate the prognostic role of the rs822336 G>C and rs822337 T>A polymorphisms of the PD-L1 (Programmed Death-Ligand 1) in TNBC patients. Materials and methods: Formalin-fixed paraffin-embedded tissues from 114 TNBC patients and blood samples from 124 healthy donors were genotyped, and subsequently extensive statistical analysis was performed in order to investigate the clinical value of these polymorphism in TNBC. Results: Regarding rs822336 G>C, we found that the CG genotype was the most common among women that harbored Stage IV breast tumors (81.8%; p = 0.022), recurred (38.9%; p = 0.02) and died (66.7%; p = 0.04). Similarly, the rs822337 T>A genotype AA is associated with worse prognosis, since it was the most common genotype among stage IV tumors (72.7%; p = 0.04) and in TNBC patients that relapsed (75%; p = 0.021) and died (81.5%; p = 0.004). Our statistical analysis revealed that the rs822336 G>C genotype CG and the rs822337 T>A allele AA are strongly associated with inferior DFS and OS intervals. Moreover, it was revealed that women harboring mutated genotypes of both SNPs had shorter disease-free (Kaplan−Meier; p = 0.037, Cox analysis; p = 0.04) and overall (Kaplan−Meier; p = 0.025, Cox analysis; p = 0.03) survival compared to patients having normal genotype of at least one SNP. Multivariate analysis also showed that the presence of mutated genotypes of both SNPs is a strong and independent marker for predicting shorter DFS (p = 0.02) and OS (p = 0.008). Conclusion: Our study revealed that PD-L1 rs822336 G>C and rs822337 T>A polymorphisms were differentially expressed in our cohort of TNBC patients, and that this distribution was associated with markers of unfavorable prognosis and worse survival.

PD-L1 rs2890658 Polymorphism Increases Risk for Non-Small-Cell Lung Cancer in Northern China Population Based on Experimental Data and Meta-Analysis

Purpose

To dig the PD-L1 rs2890658 polymorphism with susceptibility of non-small-cell lung cancer (NSCLC) in northern China.

Patients and Methods

There were 600 NSCLC patients and 600 age and sex matched controls from the same ethnic origin recruited in the present research. Polymerase chain reaction-restriction fragment length polymorphism method genotyped PD-L1 rs2890658 polymorphism. PubMed and Embase were searched to get eligible literature for meta-analysis. The association between PD-L1 rs2890658 polymorphism and NSCLC risk was calculated with odds ratio and 95% confidence interval.

Results

It is more likely that individuals who have CC genotype and C allele are 2.15 and 1.41 times to develop NSCLC compared with individuals with AA genotype and A allele, respectively. Meta-analysis showed that the individuals who have C allele and CA genotype increased the risk of suffering from NSCLC.

Conclusion

PD-L1 rs2890658 polymorphism increased NSCLC risk in northern China population and it might predict the occurrence of NSCLC.

Pilot Study: Immune Checkpoints Polymorphisms in Greek Primary Breast Cancer Patients

Background: Breast cancer is the most prevalent and second leading cause of cancer-related death in women worldwide. Despite early detection and better treatment therapies, 30% of early-stage breast cancer patients still develop recurrent disease. Breast cancer is a heterogeneous disease comprising several molecular subtypes, commonly classified into clinical subtypes based on the hormone receptor status. These subtypes included luminal A and luminal B, which have different prognoses. Breast cancer development and progression involve many factors. Polymorphisms of PD-1, PD-L1, and PD-L2 genes have been previously associated with high risk and prognosis of cancer. However, no studies have associated PD-1, PD-L1, and PD-L2 polymorphisms with primary breast cancer subtypes. Hence, this study evaluated functional single nucleotide polymorphisms of PD-1, PD-L1, and PD-L2 with primary breast cancer subtypes, luminal A, and luminal B. In addition, we evaluated the PD-L1 protein expression in relation to primary breast cancer subtypes and stages. Results: There were no significant differences in the allele frequencies of PD-1 polymorphisms (rs2227981 G>A, rs7421861 A>G, and rs11568821 C>T) and PD-L1 polymorphisms (rs10815225 C>T and rs2282055 T>G) when compared with the general European population. However, a significant difference was detected in one of the PD-L2 polymorphisms (rs1009759 A>G), with the G allele higher in breast cancer patients than in the general European population. A higher prevalence of the T allele of PD-L1 polymorphism rs2282055 T>G was observed in luminal B breast cancer patients compared with luminal A. No significant difference was detected in other polymorphisms. We also observed that the PD-L1 rs2282055 TT genotype was more prevalent in luminal B breast cancer patients compared with luminal A. Our results found no association of the selected SNPs in the PDCD1 gene with breast cancer risk. Similarly, the protein expression data showed that PD-L1 and PD-L2 are associated with an aggressive phenotype, Luminal B, and advanced breast cancer stage. Conclusion: These findings suggest that immune checkpoint polymorphisms are associated with the risk and subtypes of breast cancer.

Genetic Variation of PD-L1 Gene Affects its Expression and Is Related to Clinical Outcome in Epithelial Ovarian Cancer

Objective

This study aims to investigate the effect of polymorphisms of programmed cell death-ligand 1 (PD-L1) on the risk and patient’s outcomes of epithelial ovarian cancer (EOC).

Methods

Totally, 568 patients and 532 healthy women were included. Three polymorphisms in the PD-L1 gene, rs2297136, rs4143815 and rs4742098, were genotyped by the polymerase chain reaction/ligase detection reaction (PCR-LDR). Survival analysis was performed in 234 patients (received primary debulking surgery followed by platinum-based chemotherapy).

Results

Patients with the rs2297136 AG + GG genotypes had shorter progression-free survival (PFS) (hazard ratio (HR)=1.44, 95% CI=1.03-2.01) and overall survival (OS) (HR=1.55, 95% CI=1.06-2.27) than those with the AA genotype. Moreover, the mRNA and protein expression levels of PD-L1 in EOC tissues with the rs2297136 AG + GG genotypes were remarkably higher than those with the AA genotype (P=0.032 and P=0.047, respectively). Survival analysis showed that high expression of PD-L1 mRNA was remarkably associated with worse 10-year PFS (HR=1.55, 95% CI=1.28-1.88) and OS (HR=1.51, 95% CI=1.00-2.28) in EOC patients.

Conclusions

The rs2297136 may not only effectively influence the expression of PD-L1, but also is significantly associated with EOC patients’ outcomes.

Association of PD-1 and PDL-1 gene polymorphisms with colorectal cancer risk and prognosis

BACKGROUND

Programmed Cell Death-1 (PD-1) together with Programmed Death Ligand 1 (PDL-1) have crucial roles in anti-tumor immune response, cancer susceptibility and prognosis. Since PD-1 and PDL-1 have been considered as important genetic risk factors in cancer development and their functions can be affected by polymorphic sites, we investigated the effects of PD-1 rs2227981, rs2227982, rs36084323 and PDL-1 rs2282055, rs822336 gene polymorphisms on colorectal cancer (CRC) risk and prognosis in Turkish subjects.

METHODS AND RESULTS

Our study group consisted of 5-FU or Capacitabine prescribed CRC diagnosed patients and healthy controls. Genotype analyses of PD1 and PDL-1 polymorphisms were performed with Agena MassARRAY platform. rs36084323 CT genotype frequency was found to be higher in controls compared to cases (p < 0.001). rs36084323 CT genotype was highly associated with reduced CRC risk compared to CC genotype (OR 0.068, 95% CI 0.022-0.211, p < 0.001). In adjusted analysis, rs2282055 GG genotype was found to be associated with reduced CRC risk (OR 0.271, 95% CI 0.078-0.940, p = 0.040). rs2282055 TT genotype was found to be related to longer progression-free (Bonferroni corrected Log rank p = 0.013) and overall survival (Bonferroni corrected Log rank p = 0.009) to that of GG genotypes. Patients with rs822336 GC+CC genotypes showed longer overall survival times compared to GG (Log rank p = 0.044).

CONCLUSIONS

According to our results, PD-1 rs822336 G > C polymorphism might be useful in predicting CRC prognosis. PDL-1 rs2282055 T > G polymorphism might be useful in predicting both CRC risk and prognosis. Further studies should be conducted in larger and different populations to clear the roles of PD-1 and PDL-1 polymorphisms in CRC risk and prognosis.

Current understanding of cancer-intrinsic PD-L1: regulation of expression and its protumoral activity

In the last decade, we have witnessed an unprecedented clinical success in cancer immunotherapies targeting the programmed cell-death ligand 1 (PD-L1) and programmed cell-death 1 (PD-1) pathway. Besides the fact that PD-L1 plays a key role in immune regulation in tumor microenvironment, recently a plethora of reports has suggested a new perspective of non-immunological functions of PD-L1 in the regulation of cancer intrinsic activities including mesenchymal transition, glucose and lipid metabolism, stemness, and autophagy. Here we review the current understanding on the regulation of expression and intrinsic protumoral activity of cancer-intrinsic PD-L1.

PD-1/PD-L1 blockade: Prospectives for immunotherapy in cancer and autoimmunity

Immune checkpoint blockade therapy (ICBT) has become a successful cancer treatment approach in the field of cancer immunotherapy. Blockade of programmed death 1 (PD-1) and programmed death-ligand 1 (PD-L1) with monoclonal antibodies have been known as successful examples of cancer immunotherapy in recent years. Although ICBT has been shown to be beneficial in cancers, such benefits have only been seen in a portion of cancer patients. In this regard, enhancing the therapeutic effects of inhibiting PD-1 and PD-L1 and reducing the side effects of this approach can be considered as a potential approach in a successful ICBT. In this review, we have highlighted new viewpoints regarding improving the therapeutic effect of PD-1 and PD-L1 blockades in cancer therapy. Besides, their expression levels as a biomarker with prognostic value, their role in intestinal microbiota modulation, combination therapy, and immune-related side effects (irAEs) have been discussed.

miR-105-5p regulates PD-L1 expression and tumor immunogenicity in gastric cancer

Cancer immunotherapies targeting the interaction between Programmed death 1 (PD-1) and Programmed death ligand 1 (PD-L1) have recently been approved for the treatment of multiple cancer types, including gastric cancer. However, not all patients respond to these therapies, while some eventually acquire resistance. A partial predictive biomarker for positive response to PD-1/PD-L1 therapy is PD-L1 expression, which has been shown to be under strict post-transcriptional control in cancer. By fractionating the PD-L1 3' untranslated region (3'UTR) into multiple overlapping fragments, we identified a small 100-nucleotide-long cis-acting region as being necessary and sufficient for post-transcriptional repression of PD-L1 expression in gastric cancer. In parallel, we performed a correlation analysis between PD-L1 expression and all host miRNAs in stomach cancer patient samples. A single miRNA, miR-105-5p, was predicted to bind to the identified cis-acting 3'UTR region and to negatively correlate with PD-L1 expression. Overexpression of miR-105-5p in gastric cancer cell lines resulted in decreased expression of PD-L1, both at the total protein and surface expression levels, and induced CD8⁺ T cell activation in co-culture assays. Finally, we show that expression of miR-105-5p in gastric cancer is partly controlled by DNA methylation of a cancer- and germline-specific promoter of its host gene, GABRA3. Dysregulation of miR-105-5p is observed in many cancer types and this study shows the importance of this miRNA in controlling the immunogenicity of cancer cells, thus highlighting it as a potential biomarker for PD-1/PD-L1 therapy and target for combinatorial immunotherapy.

Association Between PDL1 Genetic Variation and Efficacy of Apatinib Monotherapy in Patients with Previously Treated Advanced NSCLC: A Real-World Retrospective Study

Background

This study aimed to explore associations between PDL1 polymorphisms and efficacy of apatinib for patients with previously treated advanced non-small cell lung cancer (NSCLC) in a real-world setting.

Methods

We retrospectively recruited 148 patients with previously treated advanced NSCLC from January 2015 to December 2019 continuously. Clinical efficacy in patients receiving apatinib treatment was evaluated. Adverse reactions were documented during treatment. Biological specimens of peripheral blood and cancer tissue biopsies were obtained for the genotyping of genetic variations in PDL1 and corresponding gene-mRNA expression, respectively. Univariate association analysis between the status of PDL1 genetic variations and survival was performed with Kaplan-Meier survival analysis.

Results

The objective response rate of the 148 patients was 17.6% and disease-control rate 68.9%. Prognostic data suggested that median progression-free survival (PFS) was 3.8 (95% CI 3.13-4.47) months and median overall survival (OS) 10.5 (95% CI 9.06-11.95) months. Regarding PDL1 genetic variation, only rs2297136 was of clinical significance. Prognosis analysis revealed that PFS and OS for the rs2297136 genotype were significantly different. Median PFS of patients with TC/CC and TT genotypes was 3 and 4.5 months, respectively (P=0.006). Median OS of the two genotypes was 9 and 11.6 months, respectively (P=0.04). Furthermore, the safety profile suggested that the most common adverse reactions were hypertension, dermal toxicity, fatigue, and oral toxicity. This study failed to find any significant association between adverse reactions and rs2297136. Interestingly, mRNA-expression analysis demonstrated that mRNA expression of PDL1 in biopsy cancer-tissue specimens was significantly different based on rs2297136-genotype status (P<0.001).

Conclusion

The PDL1 polymorphism rs2297136 could be used as a potential biomarker for the prognosis of patients with NSCLC receiving apatinib monotherapy.

Clinicopathological and Prognostic Significance of Immunoscore and PD-L1 in Intrahepatic Cholangiocarcinoma

Background

An increasing amount of evidence reveals that immunosuppression is a major issue in cancer progression. The association of immunoscore (IS) and its impact on clinical outcome have been studied in many tumor types, but its significance in intrahepatic cholangiocarcinoma (ICC) is poorly known.

Methods

By immunohistochemistry, CD3 and CD8 expressions were assessed in tissue samples of 50 cases of postoperative ICC. The IS was determined by analyzing CD3+ and CD8+ expression data in different areas (intratumor and invasion margins). The relationship between IS and clinicopathological characteristics, including the overall survival (OS) and recurrence-free survival (RFS), was analyzed. In addition, PD-L1, a major regulator of immune escape, was also assessed in tumor cells by immunohistochemistry.

Results

IS was related to histological differentiation (P=0.026), the presence of lymphoid metastasis (P=0.034), and TNM clinical stages (P = 0.031) of ICC. High IS was significantly associated with better RFS (P=0.033) and OS (P=0.014). IS was an independent prognostic factor for better OS in multivariate analysis. PD-L1 expression was closely related to tumor vascular invasion (P=0.044). Although there was no association between PD-L1 expression and IS, high PD-L1 expression in tumor cells indicated poor RFS (P=0.017) and OS (P=0.004) in ICC.

Conclusion

The IS and PD-L1 may be used as a complement to the TNM system for predicting the prognosis of patients with ICC.

Future of immune checkpoint inhibitors: focus on tumor immune microenvironment

Immunotherapy has become a powerful clinical strategy in cancer treatment. Immune checkpoint inhibitors (ICIs) have opened a new era for cancer immunotherapy. Nowadays, the number of immunotherapy drug approvals has increased, with numerous treatment options in clinical and preclinical development. However, there remain some obstacles to improve the efficacy of ICIs further. The tumor immune microenvironment (TIME) consists of cancer cell, immune cells and cytokines, et cetera. The dynamics of TIME determine the efficacies of ICIs. Although the ICIs showed manageable toxicity, immune-related adverse effects (irAEs) are still unignorable for clinicians. Since some primary resistance mechanisms exist in TIME, ICIs can only show effects in individual cancer patients. Even for the patients who responded, acquired resistance will occur to neutralize the effect of ICIs. Understanding how to increase the response rates and overcome the resistance to various classes of ICIs is the key to improving clinical efficacy. Besides the novel ICIs in development, there are some approaches to establish combination therapies are underway to improve further the efficacies of ICIs in treating cancer patients. Here, we describe the complicated TIME and state quo of ICIs to prospect the future of ICIs in cancer treatment.

Influence of Programmed Death Ligand-1-Gene Polymorphism rs822336 on the Prognosis and Safety of Postoperative Patients with NSCLC Who Received Platinum-Based Adjuvant Chemotherapy

Purpose

This study was done to investigate the influence of PDL1-gene polymorphism on the prognosis and safety of postoperative patients with non–small cell lung cancer (NSCLC) who had received platinum-based adjuvant chemotherapy.

Methods

A total of 289 postoperative patients with NSCLC who had received platinum-based adjuvant chemotherapy from January 2012 to June 2019 participated in this study. Recurrence status and adverse reactions were documented during adjuvant chemotherapy. Overall survival (OS) data were obtained through telephone follow-up. DNA extracted from hematologic specimens was genotyped for PDL1-gene polymorphism. Associations between genotype status and prognosis were assessed using Kaplan–Meier survival analysis, and multivariate adjustment was performed using Cox regression analysis.

Results

Median disease-free survival of the 289 patients with NSCLC was 3.3 years and median OS 4.9 years. With regard to the PDL1 gene polymorphism, only rs822336 was of clinical significance in the subsequent analysis. The minor-allele frequency of rs822336 was 0.21, and distribution of the three genotypes was in accordance with the Hardy–Weinberg equilibrium (P=0.807). Survival analysis according to genotype status suggested that median disease-free survival of patients with GG and GC/CC genotypes was 2.8 and 4.1 years, respectively (P=0.01). Median OS of patients with GG and GC/CC genotypes was 4.1 and 5.4 years, respectively (P=0.008). However, the safety analysis failed to find a significant association between the polymorphism and adverse reactions. Interestingly, expression analysis of RNA extracted from peripheral blood mononuclear cells indicated that PDL1-mRNA expression of patients with the GG genotype was significantly higher than for the GC/CC genotype (P<0.001).

Conclusion

The prognosis of postoperative patients with NSCLC who have received platinum-based adjuvant chemotherapy may be influenced by the rs822336 polymorphism through mediation of the mRNA expression of PDL1.

Current status of immune checkpoint inhibitors for gastric cancer

Recent breakthrough results from immune checkpoint inhibitors (ICI) have paved the way to a new era of cancer immunotherapy. In particular, inhibition of programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis with ICI including nivolumab and pembrolizumab has been emerging as a novel treatment strategy for advanced gastric cancers (GC). In a meta-analysis for anti-PD-1/PD-L1 therapy in GC, the objective response rate was 12.0% and the disease control ratio was 34.7%. The ICI treatment in GC provided modest survival benefit and especially, anti-PD-1 treatment could improve the 12-month and 18-month overall survival rate and prolonged the duration of the response. Moreover, it is likely that anti-PD-1/PD-L1 therapy is more effective in subgroups with microsatellite instability-high, Epstein-Barr virus-positive or high mutation burden in advanced GC. The next steps for developing ICI in GC are mainly two challenges as follows. First is the identification of accurate biomarkers that can predict the response to ICI. The second challenge is the clinical development of combinatorial approaches to maximize the efficacy of ICI. In this review, recent advances in ICI for GC are discussed from a viewpoint of translational aspect including biomarkers and tumor microenvironment, and from a viewpoint of clinical aspects including combination therapies.

Multi-layered control of PD-L1 expression in Epstein-Barr virus-associated gastric cancer

Gastric cancer (GC) is the fifth most common cancer worldwide. In approximately 10% of GC cases, cancer cells show ubiquitous and monoclonal Epstein-Barr virus (EBV) infection. A significant feature of EBV-associated GC (EBVaGC) is high lymphocytic infiltration and high expression of immune checkpoint proteins, including programmed death-ligand 1 (PD-L1). This highlights EBVaGC as a strong candidate for immune checkpoint blockade therapy. Indeed, several recent studies have shown that EBV positivity in GC correlates with positive response to programmed cell death protein 1 (PD-1)/PD-L1 blockade therapy. Understanding the mechanisms that control PD-L1 expression in EBVaGC can indicate new predictive biomarkers for immunotherapy, as well as therapeutic targets for combination therapy. Various mechanisms have been implicated in PD-L1 expression regulation, including structural variations, post-transcriptional control, oncogenic activation of intrinsic signaling pathways, and increased sensitivity to extrinsic signals. This review provides the most recent updates on the multilayered control of PD-L1 expression in EBVaGC.

The influence of PD-L1 genetic variation on the prognosis of R0 resection colorectal cancer patients received capecitabine-based adjuvant chemotherapy: a long-term follow-up, real-world retrospective study

PURPOSE

This study investigated the influence of PD-L1 genetic variation on the prognosis of R0 resection colorectal cancer (CRC) patients who received capecitabine-based adjuvant chemotherapy in real world.

METHODS

A total of 315 CRC patients underwent R0 surgical resection and received capecitabine-based adjuvant chemotherapy were included. Clinical characteristics were collected from the hospital record system, prognosis was obtained by telephone follow-up. Peripheral blood and peripheral blood mononuclear cell (PBMC) specimen of CRC patients were performed for the genotyping of polymorphism and mRNA expression of PD-L1, respectively. Analysis on the association between genotypes and prognosis was conducted.

RESULTS

The median disease-free survival (DFS) of the 315 CRC patients was 5.1 years, the median overall survival (OS) was 6.0 years. Regarding the PD-L1 gene polymorphism analysis, the prevalence of 901T>C among the CRC patients was as follows: TT genotype 221 cases (70.16%), TC genotype 86 cases (27.30%), CC genotype 8 cases (2.54%), the minor allele frequency was 0.16, the distribution of three genotypes was in accordance with Hardy-Weinberg equilibrium (P = 0.915). Moreover, the prognosis analysis indicated that the median DFS of patients with TT and TC/CC genotype was 5.4 and 4.0 years, respectively (P = 0.008). The median OS of patients with the two genotypes was 6.4 and 5.0 years (P = 0.007). The multivariate Cox regression analysis showed that the TC/CC genotypes were an independent factor for DFS (odds ratio = 1.56, P = 0.018). Furthermore, the mRNA expression results indicated that the mRNA expression of PD-L1 in PBMC of the patients with TC/CC genotype was significantly higher than patients with TT genotype (P < 0.001).

CONCLUSION

The prognosis of R0 resection CRC patients received capecitabine-based adjuvant chemotherapy in real world may be influenced by PD-L1 901T>C polymorphism through mediation of the mRNA expression of PD-L1.

Expression of Programmed Death Ligand 1 Is Associated with the Prognosis of Intrahepatic Cholangiocarcinoma

BACKGROUND

Programmed death ligand 1 (PD-L1) is expressed in many malignancies and plays a critical role in escape from immune surveillance through inhibition of its receptor programmed death 1. The role of PD-L1 in intrahepatic cholangiocarcinoma (ICC) and mechanisms of its regulation, however, remain largely unknown.

AIMS

To analyze the expression and prognostic significance of PD-L1 in ICC and to study the regulatory mechanisms of PD-L1.

METHODS

Samples were obtained from 125 patients diagnosed with ICC in the Eastern Hepatobiliary Surgery Hospital from January 2012 to January 2013. The records of each patient were analyzed to examine the relationship between PD-L1 and clinical data. In vitro experiments were performed to investigate the relationship between PD-L1 and the IL-6/mTOR signaling pathway and the feedback mechanism pathway of PD-L1.

RESULTS

Expression of PD-L1 is closely related to tumor vascular invasion, lymphatic metastasis and TNM staging. High PD-L1 expression is closely related to poor prognosis in ICC. Mechanically, IL-6 induces PD-L1 expression through mTOR signaling in ICC cells. In addition, PD-L1 has a negative feedback inhibition effect on AKT signaling.

CONCLUSIONS

In summary, high PD-L1 expression was found to be associated with poor prognosis. The IL-6/mTOR pathway upregulates expression of PD-L1, thus promoting tumor invasion, and PD-L1 negatively inhibits the AKT pathway.

Association between PD-1 and PD-L1 Polymorphisms and the Risk of Cancer: A Meta-Analysis of Case-Control Studies

A number of case-control studies regarding the association of the polymorphisms in the programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) genes with the risk of cancer have yielded inconsistent findings. Therefore, we have conducted a comprehensive, updated meta-analysis study to identify the impact of PD-1 and PD-L1 polymorphisms on overall cancer susceptibility. The findings revealed that PD-1 rs2227981 and rs11568821 polymorphisms significantly decreased the overall cancer risk (Odds Ratio (OR) = 0.82, 95% CI = 0.68-0.99, p = 0.04, TT vs. CT+CC; OR = 0.79, 95% CI = 0.67-0.94, p = 0.006, AG vs. GG, and OR = 0.82, 95% CI = 0.70-0.96, p = 0.020, AG+AA vs. GG, respectively), while PD-1 rs7421861 polymorphism significantly increased the risk of developing cancer (OR = 1.16, 95% CI = 1.02-1.33, p = 0.03, CT vs. TT). The PD-L1 rs4143815 variant significantly decreased the risk of cancer in homozygous (OR = 0.62, 95% CI = 0.41-0.94, p = 0.02), dominant (OR = 0.70, 95% CI = 0.50-0.97, p = 0.03), recessive (OR = 0.76, 95% CI = 0.60-0.96, p = 0.02), and allele (OR = 0.78, 95% CI = 0.63-0.96, p = 0.02) genetic models. No significant association between rs2227982, rs36084323, rs10204525, and rs2890658 polymorphisms and overall cancer risk has been found. In conclusions, the results of this meta-analysis have revealed an association between PD-1 rs2227981, rs11568821, rs7421861, as well as PD-L1 rs4143815 polymorphisms and overall cancer susceptibility.

Recent Findings in the Regulation of Programmed Death Ligand 1 Expression

With the recent approvals for the application of monoclonal antibodies that target the well-characterized immune checkpoints, immune therapy shows great potential against both solid and hematologic tumors. The use of these therapeutic monoclonal antibodies elicits inspiring clinical results with durable objective responses and improvements in overall survival. Agents targeting programmed cell death protein 1 (PD-1; also known as PDCD1) and its ligand (PD-L1) achieve a great success in immune checkpoints therapy. However, the majority of patients fail to respond to PD-1/PD-L1 axis inhibitors. Expression of PD-L1 on the membrane of tumor and immune cells has been shown to be associated with enhanced objective response rates to PD-1/PD-L1 inhibition. Thus, an improved understanding of how PD-L1 expression is regulated will enable us to better define its role as a predictive marker. In this review, we summarize recent findings in the regulation of PD-L1 expression.

CDK6 3'UTR polymorphisms alter the susceptibility to cervical cancer among Uyghur females

AIMS

Cyclin dependent kinase 6 (CDK6) plays a crucial role in malignant tumor whereas less is reported in cervical cancer development. The aim of this study was to evaluate the effects of CDK6 3' untranslated region (3'UTR) polymorphisms on cervical cancer susceptibility among Uyghur females.

METHODS

The genotypes of the six CDK6 variants (rs8179, rs42032, rs42033, rs42034, rs42035, and rs42038) were identified among 306 cervical cancer cases and 310 healthy controls with the Agena MassARRAY platform. The associations of the candidate single nucleotide polymorphisms (SNPs) with the cervical cancer risk were evaluated under genetic models using conditional logistic regression analysis. Bioinformatics analysis was performed for SNP function prediction with the online databases. The expression differences between tumor tissues and normal cervix samples were also examined by Real-time PCR.

RESULTS

CDK6 rs8179 and rs42033 were correlated to the decreased risk of cervical cancer in Uyghurs under the allele model (rs8179 and rs42033: OR = 0.60, 95% CI: 0.37-0.99, p = 0.043) and log-additive model (rs8179 and rs42033: OR = 0.62, 95% CI: 0.38-1.00, p = 0.047). Rs8179, rs42032, and rs42033 were associated with susceptibility to high-grade cervical cancer in different genetic models as well (p < 0.05). Dataset-based analysis also uncovered the potential effects of these significant SNPs. In addition, aberrant expression of CDK6 were detected in cervical tumors.

CONCLUSIONS

Our results suggested the relationships between CDK6 3'UTR polymorphisms and cervical cancer pathogenesis, and the involvement of CDK6 in cervical cancer development among Uyghur females.