Predictive relevance of programmed cell death protein 1 and tumor-infiltrating lymphocyte expression in papillary thyroid cancer

Chronic Lymphocytic Thyroiditis with Oncocytic Metaplasia Influences PD-L1 Expression in Papillary Thyroid Carcinoma

BACKGROUND

Despite the increasing recognition of PD-L1 as predictor of immunotherapeutic response in various malignancies, its role and prognostic significance in thyroid cancer remain underexplored and subject to debate. This study begins to address this gap by comprehensively analyzing PD-L1 expression in papillary thyroid carcinoma (PTC) and investigating its correlation with key clinicopathological variables.

METHODS

We conducted immunohistochemistry (IHC) to assess PD-L1 expression in whole-tissue sections from 121 primary papillary thyroid carcinoma (PTC) cases. We then analyzed the correlations between PD-L1 expression and various clinicopathological variables.

RESULTS

PD-L1 expression was detected in 33.1% of papillary thyroid carcinomas (PTCs), predominantly exhibiting weak to moderate intensity. Notably, this study found no significant correlation between PD-L1 expression and various clinicopathological variables. The lack of association with traditional factors such as age, sex, histological subtype, and tumor size suggests the complex and multifaceted nature of PD-L1 regulation in PTC. Multivariate logistic regression analysis identified chronic lymphocytic thyroiditis with oncocytic metaplasia as the sole independent predictor of PD-L1 expression (P = 0.014), underlining the potential influence of the tumor microenvironment on immune checkpoint expression in PTC.

CONCLUSIONS

Our study underscores the intricate interplay between chronic lymphocytic thyroiditis with oncocytic metaplasia and PD-L1 expression in papillary thyroid carcinoma. The observed link suggests a potential avenue for therapeutic intervention using anti-PD-1/PD-L1 therapies in surgery-refractory PTC. Understanding the dynamics of immune checkpoint regulation in the context of the tumor microenvironment is crucial for devising effective treatment strategies. Future research endeavors should delve deeper into the molecular mechanisms underlying this interaction and explore its implications for patient outcomes. As the field of immunotherapy continues to evolve, our findings contribute valuable insights into the complex immunological landscape of thyroid cancer.

Update regarding the role of PD-L1 in oncocytic thyroid lesions on cytological samples

AIMS

Several papers have shown that programmed death-ligand 1 (PD-L1) expression is a relevant predictive biomarker in anti-PD-L1 cancer immunotherapy. While its role in several human cancers is correlated with poor prognosis and resistance to anticancer therapies, in thyroid cancers the role of PD-L1 remains questionable. Few articles have studied PD-L1 in thyroid fine-needle aspiration cytology (FNAC), demonstrating a possible correlation with papillary thyroid carcinoma. However, its role in oncocytic thyroid lesions remains controversial. We accordingly examine the performance of PD-L1 immunostaining in liquid based cytology (LBC) from oncocytic lesions.

METHODS

From January 2019 to March 2021, 114 thyroid lesions diagnosed by FNAC from lesions with a predominant oncocytic component, were enrolled for evaluation by PD-L1 immunostaining on both LBC and corresponding histology samples.

RESULTS

The FNAC cohort included 51 benign (B, negative controls), 4 atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS), 57 follicular lesions (follicular neoplasm/suspicious for FN, FN/SFN) and 2 suspicious for malignancy (SFM) cases. Fifty-four cases (11B, 2 AUS/FLUS, 39 FN/SFN and 2 SFM) had histological follow-up including: 1B case resulted as a hyperplastic oxyphilic nodule in Hashimoto thyroiditis (HT), 10B as goitre, 2 AUS/FLUS cases as oncocytic adenomas (OAs); 39 FN/SFN included 27 OAs, 4 FA and 8 oncocytic follicular carcinoma (OFC). The two SFM cases were diagnosed on histopathology as OAs. Increased plasma membrane and cytoplasmic PD-L1 expression were found in 47 cases of the LBC cases (41.2%). Among the histological series, 67.3% of OAs and 75% of OFC had PD-L1 expression, while negative PD-L1 was found in hyperplastic oncocytic cells in HT. A positivity in more than 30% of the neoplastic cells was found in 72.9% of the cases including six OFC.

CONCLUSIONS

These data suggest that PD-L1 expression is expressed in oncocytic thyroid lesions. While weak PD-L1 expression failed to discriminate benign from malignant lesions, OFC demonstrated more intense cytoplasmic and membranous expression.

A cell cycle-related lncRNA signature predicts the progression-free interval in papillary thyroid carcinoma

The cell cycle plays a vital role in tumorigenesis and progression. Long non-coding RNAs (lncRNAs) are key regulators of cell cycle processes. Therefore, understanding cell cycle-related lncRNAs (CCR-lncRNAs) is crucial for determining the prognosis of papillary thyroid carcinoma (PTC). RNA-seq and clinical data of PTC were acquired from The Cancer Genome Atlas, and CCR-lncRNAs were selected based on Pearson's correlation coefficients. According to univariate Cox regression, least absolute shrinkage and selection operator (LASSO), and multivariate Cox regression analyses, a five-CCR-lncRNA signature (FOXD2-AS1, LOC100507156, BSG-AS1, EGOT, and TMEM105) was established to predict the progression-free interval (PFI) in PTC. Kaplan-Meier survival, time-dependent receiver operating characteristic curve, and multivariate Cox regression analyses proved that the signature had a reliable prognostic capability. A nomogram consisting of the risk signature and clinical characteristics was constructed that effectively predicted the PFI in PTC. Functional enrichment analyses indicted that the signature was involved in cell cycle- and immune-related pathways. Furthermore, we also analyzed the correlation between the signature and immune cell infiltration. Finally, we verified the differential expression of CCR-lncRNAs in vitro using quantitative real-time polymerase chain reaction. Overall, the newly developed prognostic risk signature based on five CCR-lncRNAs may become a marker for predicting the PFI in PTC.

Association of Programmed Death-Ligand 1 Expression with Aggressive Histological Types of Thyroid Carcinoma

Introduction

Immunohistochemical expression of programmed death-ligand 1 (PD-L1) has become a biomarker to predict the usefulness of cancer immunotherapy using PD-1/PD-L1 blockade in a variety of advanced-stage tumours. This emerging biomarker may serve to generate novel therapies for aggressive thyroid carcinoma (TC), which has not shown optimal results with existing treatments.

Methods

The present study investigated the relevance of PD-L1 expression in aggressive histological types of TC compared with that found in less aggressive types. Surgically resected specimens were investigated, including 52 cases of TC consisting of 26 cases of aggressive histological types and 26 cases of less aggressive histological types. Immunohistochemical examinations were carried out on paraffin blocks of both groups using a mouse monoclonal primary antibody against PD-L1 (clone 22C3). PD-L1 expression was evaluated by calculating the tumour proportion score (TPS) in both groups.

Results

The results revealed a significant difference in the median TPS value of PD-L1 expression between the two groups. The TPS values were found to be higher in the group of aggressive histological types of TC compared with those in the group of less aggressive histological types. A significant difference in TPS value was also found for the extrathyroidal extension variable.

Discussion

In conclusion, the present study found a significant association between PD-L1 expression and the aggressive histological type of TC. In addition, a potential association between PD-L1 expression and the presence of extrathyroidal extension of TC was observed. These findings provide novel approaches for immunotherapy as a potential new treatment modality in patients with aggressive histological types of TC.

The prognostic significance of CXCR4 and SDF-1 in differentiated thyroid cancer depends on CD8+ density

BACKGROUND

Tumor infiltration with cytotoxic CD8+ T-cells is associated with a favorable outcome in several neoplasms, including thyroid cancer. The chemokine axis CXCR4/SDF-1 correlates with more aggressive tumors, but little is known concerning the prognostic relevance in relation to the tumor immune microenvironment of differentiated thyroid cancer (DTC).

METHODS

A tissue microarray (TMA) of 37 tumor specimens of primary DTC was analyzed by immunohistochemistry (IHC) for the expression of CD8+, CXCR4, phosphorylated CXCR4 and SDF-1. A survival analysis was performed on a larger collective (n = 456) at RNA level using data from The Cancer Genome Atlas (TCGA) papillary thyroid cancer cohort.

RESULTS

Among the 37 patients in the TMA-cohort, the density of CD8+ was higher in patients with less advanced primary tumors (median cells/TMA-punch: 12.5 (IQR: 6.5, 12.5) in T1-2 tumors vs. 5 (IQR: 3, 8) in T3-4 tumors, p = 0.05). In the TCGA-cohort, CXCR4 expression was higher in patients with cervical lymph node metastasis compared to N0 or Nx stage (CXCR4^high/low 116/78 vs. 97/116 vs. 14/35, respectively, p = 0.001). Spearman's correlation analysis of the TMA-cohort demonstrated that SDF-1 was significantly correlated with CXCR4 (r = 0.4, p = 0.01) and pCXCR4 (r = 0.5, p = 0.002). In the TCGA-cohort, density of CD8+ correlated with CXCR4 and SDF-1 expression (r = 0.58, p < 0.001; r = 0.4, p < 0.001). The combined marker analysis of the TCGA cohort demonstrated that high expression of both, CXCR4 and SDF-1 was associated with reduced overall survival in the CD8 negative TCGA cohort (p = 0.004).

CONCLUSION

These findings suggest that the prognostic significance of CXCR4 and SDF-1 in differentiated thyroid cancer depends on the density of CD8 positive T-lymphocytes. Further studies with larger sample sizes are needed to support our findings and inform future investigations of new treatment and diagnostic options for a more personalized approach for patients with differentiated thyroid cancer.

PD-L1 and PD-1 expression in thyroid follicular epithelial dysplasia: Hashimoto thyroiditis related atypia and potential papillary carcinoma precursor

Programmed cell death ligand (PD‐L1)/PD‐1 expression has been studied in a variety of cancers and blockage of PD‐L1/PD‐1 pathway is a cornerstone of immunotherapy. We studied PD‐L1/PD‐1 immunohistochemical expression in 47 thyroid gland specimens in groups of (1) Hashimoto thyroiditis (HT) only; (2) HT and follicular epithelial dysplasia (FED); and (3) HT, FED, and papillary thyroid carcinoma (PTC). PD‐1 positivity was found in immune cells, namely in lymphocytes, macrophages, and plasma cells with mean values for lymphocytes and macrophages 9% in HT group, 4% in FED group, and 4% in PTC group. PD‐L1 positivity was identified in both immune cells and in the normal epithelial cells. In the HT group, mean PD‐L1 staining on immune cells was 6%, in FED group 5%, and in PTC group 7%. The mean PD‐L1 staining on the epithelial cells in the inflammatory parenchyma was 11.7% in HT, 13.4% in FED, and 8.3% in PTC group. The mean PD‐L1 staining of FED foci was 47.2% in FED group and 33.6% in PTC group. The mean tumor proportion score (TPS) was 10.4%, and the mean combined positive score (CPS) was 15.5. At the moment, PTC is not a target of immunotherapy. However, understanding the complex issue of concurrent inflammation and autoimmunity can importantly influence the cancer treatment in future.

Analysis of anti-apoptotic PVT1 oncogene and apoptosis-related proteins (p53, Bcl2, PD-1, and PD-L1) expression in thyroid carcinoma

Background

An aberrant expression of long non‐coding RNA PVT1 has been associated with apoptosis in various cancer types. We aimed to explore the PVT1 and four apoptosis‐related proteins (p53, Bcl2, and PD‐1/PD‐L1) signature in thyroid cancer (TC).

Methods

The PVT1 expression level was measured in 64 FFPE TC paired samples by real‐time quantitative PCR. Overall and stratified analyses by different clinicopathological features were done. The apoptotic proteins were evaluated by immunohistochemistry staining.

Results

Overall analysis showed significant PVT1upregulation in TC tissues (p < 0.001). Similarly, subgroup analysis by BRAF^V600E mutation showed consistent results. Lower expression of p53 was associated with mortality (p = 0.001). Bcl2 overexpression was associated with greater tumor size (p = 0.005). At the same time, HCV‐positive cases were associated with repressed Bcl2 expression levels (54.3% in HCV‐negative vs. 6.9% in HCV‐positive cases, p = 0.011). PD‐1 expression was associated with lymph node metastasis (p = 0.004). Enhanced PD‐L1 expression in the tumor was associated with a higher tumor stage, lymphovascular invasion, and mortality risk. Kaplan–Meier curves for overall survival showed that low p53 and high PD‐L1 expressions were associated with lower survival time. The p53‐positive staining is associated with a 90% decreased mortality risk (HR = 0.10, 95%CI = 0.02–0.47, p = 0.001), while patients with high PD‐L1 were five times more likely to die (HR = 4.74, 95%CI = 1.2–18.7, p = 0.027).

Conclusion

Our results confirm the upregulation of PVT1 in TC. The apoptosis‐related proteins (p53, Bcl2, and PD‐1/PD‐L1) showed different prognostic utility in TC patients; in particular, low p53 and high PD‐L1 expressions associated with low survival times. Further large‐scale and mechanistic studies are warranted.

Prognostic Value of Programmed Death Ligand-1 Expression in Solid Tumors Irrespective of Immunotherapy Exposure: A Systematic Review and Meta-Analysis

BACKGROUND

The programmed cell death-1/programmed cell death ligand-1 (PD-L1) pathway, which plays a crucial role in cancer immune surveillance, is the target of several approved immunotherapeutic agents and is used as a predictive biomarker in some solid tumors. However, its use as a prognostic marker (i.e., regardless of therapy used) is not established clearly with available data demonstrating inconsistent prognostic impact of PD-L1 expression in solid tumors.

METHODS

We conducted a systematic literature search of electronic databases and identified publications exploring the effect of PD-L1 expression on overall survival and/or disease-free survival. Hazard ratios were pooled in a meta-analysis using generic inverse-variance and random-effects modeling. We used the Deeks method to explore subgroup differences based on disease site, stage of disease, and method of PD-L1 quantification.

RESULTS

One hundred and eighty-six studies met the inclusion criteria. Programmed cell death ligand-1 expression was associated with worse overall survival (hazard ratio 1.33, 95% confidence interval 1.26-1.39; p < 0.001). There was significant heterogeneity between disease sites (subgroup p = 0.002) with pancreatic, hepatocellular, and genitourinary cancers associated with the highest magnitude of adverse outcomes. Programmed cell death ligand-1 was also associated with worse overall disease-free survival (hazard ratio 1.19, 95% confidence interval 1.09-1.30; p < 0.001). Stage of disease did not significantly affect the results (subgroup p = 0.52), nor did the method of quantification via immunohistochemistry or messenger RNA (subgroup p = 0.70).

CONCLUSIONS

High expression of PD-L1 is associated with worse survival in solid tumors albeit with significant heterogeneity among tumor types. The effect is consistent in early-stage and metastatic disease and is not sensitive to method of PD-L1 quantification. These data can provide additional information for the counseling of patients with cancer about prognosis.

Androgen Activity Is Associated With PD-L1 Downregulation in Thyroid Cancer

Thyroid cancer is the most prevalent endocrine malignancy in the United States with greater than 53,000 new cases in 2020. There is a significant gender disparity in disease incidence as well, with women developing thyroid cancer three times more often than men; however, the underlying cause of this disparity is poorly understood. Using RNA-sequencing, we profiled the immune landscape of papillary thyroid cancer (PTC) and identified a significant inverse correlation between androgen receptor (AR) levels and the immune checkpoint molecule PD-L1. The expression of PD-L1 was then measured in an androgen responsive-thyroid cancer cell line. Dihydrotestosterone (DHT) treatment resulted in significant reduction in surface PD-L1 expression in a time and dose-dependent manner. To determine if androgen-mediated PD-L1 downregulation was AR-dependent, we treated cells with flutamide, a selective AR antagonist, and prior to DHT treatment to pharmacologically inhibit AR-induced signaling. This resulted in a > 90% restoration of cell surface PD-L1 expression, suggesting a potential role for AR activity in PD-L1 regulation. Investigation into the AR binding sites showed AR activation impacts NF-kB signaling by increasing IkBα and by possibly preventing NF-kB translocation into the nucleus, reducing PD-L1 promoter activation. This study provides evidence of sex-hormone mediated regulation of immune checkpoint molecules in vitro with potential ramification for immunotherapies.

Diagnostic and prognostic value of tumor-infiltrating B cells in lymph node metastases of papillary thyroid carcinoma

Lymph node metastases are strongly associated with unfavorable prognosis in papillary thyroid carcinoma (PTC) patients. However, there are few sensitive or specific indicators that can diagnose or predict lymph node metastases in PTC. The objective of our study was to identify reliable indicators for the diagnosis and prediction of lymph node metastases of PTC. The PTC data set was obtained from The Cancer Genome Atlas (TCGA) cohort. Information on tumor-infiltrating immune cells in PTC was acquired using single-sample gene set enrichment analysis (ssGSEA). Then, the progression-free survival (PFS) rates of PTC patients were evaluated by Kaplan-Meier curves. A tissue microarray including 58 normal thyroid tissues and 57 PTC tissues was processed for CD19 immunohistochemistry staining. Finally, evaluation of phenotype permutations was performed using gene set enrichment analysis (GSEA). There was an appreciable association between immune infiltration and lymph node metastases in PTC. Among those immune cells, B cells and cytotoxic cells showed significant predictive accuracy for lymph node metastases in PTC. Tumor-infiltrating B cells and NK cells were associated with favorable prognosis, while tumor-associated NK CD56^bright cells were correlated with poor prognosis in PTC patients. IHC analyses of PTC further confirmed a notably negative correlation between B cell infiltration and lymph node metastases in PTC. Additionally, mutations in BRAF, a dominant cause of tumor mutation burden (TMB), were positively correlated with reduced B cell infiltration and lymph node metastases in PTC. GSEA revealed that epithelial-mesenchymal transition, IL-6/JAK/STAT3 signaling, the inflammatory response, and TNF-α signaling via the NFκB pathway were remarkably suppressed pathways in patients with BRAF mutations. Tumor-associated lymphocytic infiltration, especially B cell infiltration, provides diagnostic and prognostic value for lymph node metastases in PTC.

Peripheral Versus Intraparenchymal Papillary Thyroid Microcarcinoma: Different Morphologies and PD-L1 Expression

Peripheral localisation of papillary thyroid microcarcinoma (PTMC), in comparison with intraparenchymal PTMC (i-PTMC) is related to some clinicopathological features related with biological aggressiveness, including lymph node metastasis (LNM). The expression of PD-L1 in tumour cell has been associated with increased tumour survival, progression, and potentially an aggressive clinical course. This study evaluates the relation between clinicopathological features of PTMC, including tumour localisation, with PD-L1 immunoexpression. The study included 99 patients with the histological diagnosis of PTMC (≥ 5 mm). PD-L1 protein expression was assessed by immunohistochemistry. PTMCs were divided into the four following groups: G1- peripherally localised PTMC (p-PTMC) with PD-L1 expression; G2-p-PTMC without PD-L1 expression; G3-i-PTMC with PD-L1 expression and G4-i-PTMC without PD-L1 expression. G1 was the most frequent (n = 46; 46.5%), followed by G4 (n = 25; 25.3%) and similar distribution of G3 (n = 15; 15.2%) and G2 (n = 13; 13.1%). In comparison with other groups, G1 was significantly associated with classical morphology, invasive growth, lymphatic invasion (LI), vascular invasion (VI), psammoma bodies, intratumoral fibrosis, PD-L1 positive tumour-infiltrating lymphocytes, and multinuclear giant cells (MGCs). G4 more commonly exhibited follicular morphology, expansive/circumscribed growth, and absence of the following: intratumoural fibrosis, LI, VI, psammoma bodies, PD-L1 positive tumour-infiltrating lymphocytes, and MGCs. LNMs were significantly more frequent in G1 in comparison with the other groups (p = 0.000). In conclusion, morphology and tumour microenvironment of p-PTMC with PD-L1 expression is different from i-PTMC without PD-L1 expression. The differences between these two groups of PTMC include clinicopathological features related with biological aggressiveness such as the occurrence of LNM.

Association between programmed cell death ligand 1 expression and thyroid cancer: A meta-analysis

BACKGROUND

Programmed cell death ligand 1 (PD-L1), which is highly expressed in a variety of malignant tumors, is closely related to clinicopathological features and prognosis. However, there are few studies on the potential effects of PD-L1 on thyroid carcinoma, the incidence of which has shown an upward trend worldwide. This study aimed to explore the association between PD-L1 expression and clinicopathological features and prognosis of thyroid cancer.

METHODS

An elaborate retrieval was performed using Medline, PubMed, Cochrane Library, EMBASE, Web of Science, WanFang databases, and China National Knowledge Infrastructure to determine the association between PD-L1 expression and disease-free survival (DFS), overall survival (OS), and clinicopathological features in patients with thyroid cancer. Study selection, data extraction, risk assessment, and data synthesis were performed independently by 2 reviewers. In this meta-analysis, RevMan 5.3 and Stata 15.1 were used for bias risk assessment and data synthesis.

RESULTS

After a detailed search, 2546 cases reported in 13 articles were included in this meta-analysis. The outcomes revealed that high expression of PD-L1 in patients with thyroid cancer was associated with poor DFS (hazard ratio [HR] = 3.37, 95% confidence interval [CI] 2.54-4.48, P < .00001) and OS (HR = 2.52, 95% CI: 1.20-5.32, P = .01). High PD-L1 expression was associated with tumor size ≥2 cm, tumor recurrence, extrathyroidal extension, concurrent thyroiditis, unifocal tumor, and absence of psammoma body (P < .05). Subgroup analysis showed that positive expression of PD-L1 was related to poor prognosis for DFS of non-medullary thyroid carcinoma, and the overexpression of PD-L1 in differentiated thyroid carcinoma (DTC) was related to tumor recurrence, concurrent thyroiditis, extrathyroidal extension, unifocal DTC, late stage DTC, and BRAFV600E mutation in DTC.

CONCLUSION

PD-L1 is a significant predictor of prognosis and malignancy of thyroid cancer (especially DTC), and PD-L1 inhibitors may be a promising therapeutic option for refractory thyroid cancer in the future.

Antibody Supervised Training of a Deep Learning Based Algorithm for Leukocyte Segmentation in Papillary Thyroid Carcinoma

The quantity of leukocytes in papillary thyroid carcinoma (PTC) potentially have prognostic and treatment predictive value. Here, we propose a novel method for training a convolutional neural network (CNN) algorithm for segmenting leukocytes in PTCs. Tissue samples from two retrospective PTC cohort were obtained and representative tissue slides from twelve patients were stained with hematoxylin and eosin (HE) and digitized. Then, the HE slides were destained and restained immunohistochemically (IHC) with antibodies to the pan-leukocyte anti CD45 antigen and scanned again. The two stain-pairs of all representative tissue slides were registered, and image tiles of regions of interests were exported. The image tiles were processed and the 3,3'-diaminobenzidine (DAB) stained areas representing anti CD45 expression were turned into binary masks. These binary masks were applied as annotations on the HE image tiles and used in the training of a CNN algorithm. Ten whole slide images (WSIs) were used for training using a five-fold cross-validation and the remaining two slides were used as an independent test set for the trained model. For visual evaluation, the algorithm was run on all twelve WSIs, and in total 238,144 tiles sized 500 × 500 pixels were analyzed. The trained CNN algorithm had an intersection over union of 0.82 for detection of leukocytes in the HE image tiles when comparing the prediction masks to the ground truth anti CD45 mask. We conclude that this method for generating antibody supervised annotations using the destain-restain IHC guided annotations resulted in high accuracy segmentations of leukocytes in HE tissue images.

PD-L1 Is an Independent Prognostic Marker in Middle Eastern PTC and Its Expression Is Upregulated by BRAFV600E Mutation

Simple Summary

This study was conducted to investigate the prognostic significance of programmed death-ligand 1 (PD-L1) expression in a large cohort of Middle Eastern papillary thyroid carcinoma (PTC) patients and to explore the correlation of PD-L1 and BRAFV600E mutations in PTC tumors and cell lines. We found PD-L1 over-expression in PTC patients and it was significantly associated with aggressive clinico-pathological parameters and BRAF mutation. PTC patients with co-existing PD-L1 over-expression and BRAF mutation had a poor disease-free survival. In vitro studies showed that BRAF inhibition induces PD-L1 expression in BRAF-mutated PTC cell lines via mitogen-activated protein kinase kinase/extracellular-signal-regulated kinase (MEK/ERK) pathway activation. Silencing of PD-L1 in BRAF-mutated cell lines significantly attenuated cell growth. Our data suggest that PD-L1 could represent a useful prognostic marker for risk stratification in Middle Eastern PTC and that a programmed cell death protein 1 (PD-1)/PD-L1 inhibitor could be a potential therapeutic option for aggressive PTC cancers, such as the tall cell variant, BRAF mutation-positive patients that are unresponsive to standard PTC treatment.

Abstract

PD-L1 inhibition is a promising therapeutic target whose efficacy has been demonstrated in several cancers. Immunohistochemistry was performed to assess PD-L1 protein expression in PTC. We further conducted in vitro analysis to investigate the role of PD-L1 in regulating BRAFV600E in PTC cell lines. PD-L1 over-expression was noted in 32.4% (473/1458) of cases and significantly associated with aggressive clinico-pathological parameters. Importantly, PD-L1 was found to be an independent poorer prognostic marker. We also found PD-L1 to be significantly associated with BRAF mutation and patients with co-existing PD-L1 over-expression and BRAF mutation had a poor disease-free survival compared to patients with BRAF mutation alone. In vitro analysis showed high expression of PD-L1 in BRAF-mutated PTC cell lines compared to a BRAF wild-type cell line. Inhibition of BRAF using vemurafenib induced PD-L1 expression in BRAF-mutated cell lines without affecting cell growth. Knockdown of PD-L1 in BRAF-mutated cell lines significantly decreased the cell growth and induced apoptosis. Our data suggest that PD-L1 might represent a useful prognostic marker in Middle Eastern PTC and PD-L1 inhibition could be a potential therapeutic option for aggressive PTC cancers, such as the tall cell variant, BRAF mutation-positive patients that are unresponsive to standard treatment.

Tumor Mutation Burden Predicts Relapse in Papillary Thyroid Carcinoma With Changes in Genes and Immune Microenvironment

BACKGROUND

The risk factors of papillary thyroid carcinoma (PTC) recurrence are meaningful for patients and clinicians. Tumor mutation burden (TMB) has been a biomarker for the effectiveness of immune checkpoint inhibitor (ICI) and prognosis in cancer. However, the role of TMB and its latent significance with immune cell infiltration in PTC are still unclear. Herein, we aimed to explore the effect of TMB on PTC prognosis.

MATERIAL AND METHODS

RNA-seq and DNA-seq datasets of PTC patients were downloaded from The Cancer Genome Atlas (TCGA) database. The Gene Ontology (GO) and gene set enrichment analysis (GSEA 4.0.1) were applied further to explore potential differences in PTC patients' biological functions. The differentially expressed genes (DEGs) and immune microenvironment between the high and low TMB groups were determined.

RESULTS

TMB had the highest AUC score than other clinical indicators in ROC analysis on recurrence-free survival, and a higher TMB score was related to a worse prognosis. Further, GSEA showed a higher level of oxidative phosphorylation (OXPHOS) in the high TMB group, and four genes correlated with recurrence-free survival rate were identified. The abundance of CD8⁺ T cells and M1 macrophages in the high TMB group was significantly lower than that in the low TMB group.

CONCLUSIONS

Our study found that TMB was a better predictor variable at evaluating the risk of PTC recurrence. Moreover, TMB-related genes conferred dramatically correlated prognosis, which was worth exploring in guiding postoperative follow-up and predicting recurrence for PTC patients.

From biomarkers to therapeutic targets: the promise of PD-L1 in thyroid autoimmunity and cancer

The programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) immune checkpoint proteins hold promise as diagnostic, prognostic, and therapeutic targets for precision oncology. By restoring antitumor T cell surveillance, the high degree of effectiveness of the immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment. However, the majority of patients (65-80 %) treated with ICIs experience significant side effects, called immune-related adverse events (irAEs), resulting in autoimmune damage to various organs. Therefore, broadening the clinical applicability of these treatments to all cancer types requires an improved understanding of the mechanisms linking cancer immune evasion and autoimmunity. The thyroid is the endocrine gland the most frequently involved in autoimmunity and cancer, the growing incidence of which is raising serious public health issues worldwide. In addition, the risk of developing thyroid cancer is increased in patients with autoimmune thyroid disease and thyroid dysfunction is one of the most common irAEs, especially with PD‑1/PD-L1 blockade. Therefore, we chose the thyroid as a model for the study of the link between autoimmunity, irAEs, and cancer. We provide an update into the current knowledge of the PD‑1/PD-L1 axis and discuss the growing interest of this axis in the diagnosis, prognosis, and management of thyroid diseases within the context of autoimmunity and cancer, while embracing personalized medicine.

Immune Cell Confrontation in the Papillary Thyroid Carcinoma Microenvironment

Background

Papillary thyroid cancer has been associated with chronic inflammation. A systematic understanding of immune cell infiltration in PTC is essential for subsequent immune research and new diagnostic and therapeutic strategies.

Methods

Three different algorithms, single-sample gene set enrichment analysis (ssGSEA), immune cell marker and CIBERSORT, were used to evaluate immune cell infiltration levels (abundance and proportion) in 10 data sets (The Cancer Genome Atlas [TCGA], GSE3467, GSE3678, GSE5364, GSE27155, GSE33630, GSE50901, GSE53157, GSE58545, and GSE60542; a total of 799 PTC and 194 normal thyroid samples). Consensus unsupervised clustering divided PTC patients into low-immunity and high-immunity groups. Weighted gene coexpression network analysis (WGCNA) and gene set enrichment analysis (GSEA) were used to analyze the potential mechanisms causing differences in the immune response.

Results

Compared with normal tissues, PTC tissues had a higher overall immune level and higher abundance levels and proportions of M2 macrophages, Tregs, monocytes, neutrophils, dendritic cells (DCs), mast cells (MCs), and M0 macrophages. Compared with early PTC, advanced PTC showed higher immune infiltration and higher abundance levels and proportions of M2 macrophages, Tregs, monocytes, neutrophils, DCs, MCs, and M0 macrophages. Compared to the low-immunity group, the high-immunity group exhibited more advanced stages, larger tumor sizes, greater lymph node metastases, higher tall-cell PTCs, lower follicular PTC proportions, more BRAF mutations, and fewer RAS mutations. Epstein-Barr virus (EBV) infection was the most significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway for key module genes.

Conclusions

In human PTC, M2 macrophages, Tregs, monocytes, neutrophils, DCs, MCs, and M0 macrophages appear to play a tumor-promoting role, while M1 macrophages, CD8+ T cells, B cells, NK cells, and T follicular helper (TFH) cells (including eosinophils, γδ T cells, and Th17 cells with weak supporting evidence) appear to play an antitumor role. During the occurrence and development of PTC, the overall immune level was increased, and the abundance and proportion of tumor-promoting immune cells were significantly increased, indicating that immune escape had been aggravated. Finally, we speculate that EBV may play an important role in changing the immune microenvironment of PTC tumors.

Epithelial-to-mesenchymal transition and its association with PD-L1 and CD8 in thyroid cancer

Programmed cell death-ligand 1 (PD-L1) has recently been shown to play a role in the regulation of epithelial-to-mesenchymal transition (EMT); however, the relationship between PD-L1 expression, EMT and the inflammatory tumour microenvironment has yet to be investigated in thyroid cancer. To address this issue, we examined the expression of CD8, PD-L1 and the EMT markers E-cadherin and vimentin in a cohort of 74 papillary thyroid cancer (PTC) patients and investigated the association of these with clinicopathologic characteristics and disease-free survival (DFS). The relationship between PD-L1 and EMT was further examined in three thyroid cancer cell lines via Western blot and live cell imaging. In order to expand our in vitro findings, the normalised gene expression profiles of 516 thyroid cancer patients were retrieved and analysed from The Cancer Genome Atlas (TCGA). PD-L1 positivity was significantly higher in PTC patients exhibiting a mesenchymal phenotype (P = 0.012). Kaplan-Meier analysis revealed that PD-L1 (P = 0.045), CD8 (P = 0.038) and EMT status (P = 0.038) were all significant predictors for DFS. Sub-analysis confirmed that the poorest DFS was evident in PD-L1 positive patients with EMT features and negative CD8 expression (P < 0.0001). IFN-γ treatment induced upregulation of PD-L1 and significantly promoted an EMT phenotype in two thyroid cancer cell lines. Our findings suggest that PD-L1 signalling may play a role in stimulating EMT in thyroid cancer. EMT, CD8 and PD-L1 expression may serve as valuable predictive biomarkers in patients with PTC.

Impact of Tumor-Infiltrating Lymphocytes on Overall Survival in Merkel Cell Carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine carcinoma of the skin. As the clinical course can be variable, prognostic markers are needed to better stratify patients. Prior literature, composed of small series with limited sample size, has demonstrated that tumor-infiltrating lymphocytes (TILs) are an important prognostic marker in MCC. To validate these findings on a population level, we sought to analyze and report the prognostic value of TILs in a large national data set.

MATERIALS AND METHODS

A retrospective observational cohort study was conducted of patients with nonmetastatic MCC from 2010 to 2015 using the National Cancer Database. Individual variables trending toward significance using a univariable analysis were included in a multivariable Cox proportional hazards model to assess their independent effect on overall survival (OS). TILs were subclassified into none, nonbrisk, and brisk and the survival analysis was performed. Propensity score-weighted multivariable analysis (PS MVA) was performed to adjust for additional confounding.

RESULTS

A total of 2,182 patients met inclusion criteria: 611 (28.0%) were identified as having TILs present, and 1,571 (72.0%) had TILs absent in the tumor. On MVA, subdivision of TIL status into nonbrisk (hazard ratio [HR], 0.750; 95% confidence interval [CI], 0.602-0.933) and brisk (HR, 0.499; 95% CI, 0.338-0.735) was associated with incrementally improved OS compared with no TILs. The association of nonbrisk and brisk TILs with improved OS was retained on PS MVA (Nonbrisk: HR, 0.720; 95% CI, 0.550-0.944; Brisk: HR, 0.483; 95% CI, 0.286-0.814).

CONCLUSION

The presence of nonbrisk and brisk TILs is associated with incrementally improved OS in patients with nonmetastatic MCC in a large national data set. This pathologic feature can aid with risk stratification, estimation of prognosis, and, importantly, decision-making with respect to treatment intensification in high-risk patients.

IMPLICATIONS FOR PRACTICE

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cutaneous malignancy with variable clinical course. Prognostic markers are needed to better risk stratify patients. We present the largest retrospective observational cohort study of patients with nonmetastatic MCC using the National Cancer Database. Our analysis demonstrates an association between increasing degrees of tumor-infiltrating lymphocytes and incrementally improved survival. These conclusions improve pathologic risk stratification, and decision-making with respect to treatment intensification. Intensification may include adjuvant radiation therapy to the primary site after wide excision despite small tumor size, to the nodal basin in sentinel lymph node-negative patients, or offering closer follow-up.

Programmed Death-Ligand 1 (PD-L1) Is a Potential Biomarker of Disease-Free Survival in Papillary Thyroid Carcinoma: a Systematic Review and Meta-Analysis of PD-L1 Immunoexpression in Follicular Epithelial Derived Thyroid Carcinoma

The expression of programmed death-ligand 1 (PD-L1) is an established prerequisite for the administration of checkpoint inhibitor therapy and is of prognostic value in several cancer types. Data concerning the potential effect of PD-L1 on the prognosis of thyroid carcinoma are limited. Therefore, this study aimed to provide a systematic review of the published data on this topic. The literature was reviewed to gather and quantify evidence on the prognostic role of PD-L1 in follicular epithelial derived thyroid carcinomas and determine its association with clinicopathological parameters. A meta-analysis was performed using the DerSimonian-Laird random-effects model. The quality of studies was evaluated with the Newcastle-Ottawa Scale and a modified GRADE approach used to rate the quality of evidence. Out of 445 papers, 18 were included and 15 provided adequate data for meta-analysis. The quality of evidence ranged from low to high. PD-L1 expression was significantly associated with a reduced disease-free survival (DFS) (RR 1.63, CI 1.04-2.56, p = 0.03, I² 68%, τ² 0.19 and HR 1.90, CI 1.33-2.70, p< 0.001, I² 0%, τ² 0.00); however, no association was found with the overall survival (OS). Furthermore, a significant association was found with respect to underlying chronic lymphocytic thyroiditis and BRAFV600E mutation status in papillary thyroid carcinomas. In the subgroup analysis, the association of PD-L1 and DFS remained strong in papillary thyroid carcinoma when compared with dedifferentiated thyroid carcinomas (anaplastic and poorly differentiated thyroid carcinomas) that failed to demonstrate a significant association with respect to PD-L1. These findings underscore the role of PD-L1 immunohistochemistry as a potential prognostic biomarker of disease recurrence in patients with papillary thyroid carcinoma.

Regression of Papillary Thyroid Cancer during Nivolumab for Renal Cell Cancer

Immune checkpoint inhibitors have been recently approved for cancer treatment. Nivolumab is a monoclonal antibody specific for programmed cell death-1 (PD-1) that modulates T-cell response. It was initially used for the treatment of malignant melanoma and then approved in other cancers, such as non-small cell lung cancer and clear cell renal cell carcinoma (ccRCC). So far, the activity of nivolumab in patients with thyroid malignancies has been reported in a single case of anaplastic thyroid cancer. Here, we report the case of a patient with ccRCC who developed a papillary thyroid carcinoma (PTC) under first-line sunitinib treatment. During nivolumab, the second-line treatment for ccRCC, we unexpectedly observed a complete regression of PTC.

Clinical and prognostic value of neutrophil-lymphocyte ratio for patients with thyroid cancer: A meta-analysis

BACKGROUND

Although the malignant degree is relatively low and overall prognosis is excellent, some patients with thyroid cancer still experience metastasis during the follow-up, which leads to their possible death. Pretreatment neutrophil-to-lymphocyte ratio (NLR) has been recommended as a biomarker for the prediction of metastasis and prognosis in patients with cancers. However, its value in thyroid cancer remains inconclusive. This study aimed to comprehensively evaluate the prognostic and clinicopathological significance of NLR for thyroid cancer by a meta-analysis.

METHODS

Eligible studies were identified by searching PubMed, EMBASE, and Cochrane Library databases. The associations between NLR level and disease-free survival (DFS) or clinicopathological parameters were estimated by calculating hazard ratio (HR) or effect size with 95% confidence interval (CI).

RESULTS

Nine studies consisting of 3081 patients were enrolled. Results of meta-analysis showed that elevated NLR was not significantly associated with unfavorable DFS overall, but subgroup analysis of multivariate-adjusted studies demonstrated an elevation in pretreatment NLR predicted poor DFS (HR = 3.51, 95%CI = 1.42-8.70). Overall, a high level of NLR was significantly correlated with larger tumor size (standardized mean difference [SMD] = 0.49, 95%CI = 0.33-0.64), and metastasis status (risk ratio [RR] = 1.70, 95%CI = 1.10-2.64). The association with tumor size was still significant in the stratified analyses by country and histology type (Asian: SMD = 0.719, 95%CI = 0.44-0.98; non-Asian: SMD = 0.36, 95%CI = 0.17-0.56; medullary thyroid carcinoma: SMD = 0.57, 95%CI = 0.09-1.05; papillary thyroid carcinoma: SMD = 0.48, 95%CI = 0.31-0.64). The association between NLR and metastasis was only significant for papillary thyroid carcinoma subtype (RR = 1.82, 95%CI = 1.04-3.20).

CONCLUSION

Pretreatment NLR may serve as an excellent biomarker for prediction of tumor growth, metastasis, and prognosis in patients with thyroid cancer.

Prognostic and clinicopathological significance of PD-L1 and tumor infiltrating lymphocytes in hypopharyngeal squamous cell carcinoma

OBJECTIVES

Limited information is available regarding programmed death-ligand 1 (PD-L1) and tumor-infiltrating lymphocytes (TILs) in hypopharyngeal squamous cell carcinoma (HPSCC). Therefore, we investigated the expression of PD-L1 and the volume of TILs in HPSCC to determine whether these biomarkers were associated with patient clinicopathologic characteristics and prognosis. Furthermore, we explored p16 status and analyzed its possible correlations with clinical outcomes.

METHODS

Tissues of 111 HPSCC patients were immunohistochemically analyzed for PD-L1, CD8, CD4, and Foxp3 expression to assess the microenvironment. We also assessed the p16 status. The expression of PD-L1 and TILs were analyzed with respect to patient clinicopathologic variables and prognosis.

RESULTS

Twenty-four (21.6%) patients had PD-L1 expression in ≥1% of tumor cells. PD-L1 expression was significantly correlated with a high level of TILs (P < 0.05). Kaplan-Meier analysis showed that higher CD8+ and FoxP3+ TIL infiltration was strongly associated with superior overall survival (OS, P = 0.005 and P = 0.008) and disease-free survival (DFS, P = 0.015 and P = 0.048). Univariate and multivariate analyses confirmed that CD8+ TIL exhibited strong prognostic significance. The combination of PD-L1⁺ with CD8^high expression was a prognostic factor and was associated with better OS (P = 0.025). Moreover, p16 positivity was detected in five patients (4.5%) and was only occasionally involved in HPSCC.

CONCLUSION

Our findings indicate that high CD8 and FoxP3 expression in HPSCC contributes to longer patient survival. Although PD-L1 expression was not associated with outcome, PD-L1 positivity in combination with CD8^high expression may have greater predictive potential.

Tumor-infiltrating CD8+ T cells combined with tumor-associated CD68+ macrophages predict postoperative prognosis and adjuvant chemotherapy benefit in resected gastric cancer

Background

Tumor-infiltrating immune cells are present in various malignant tumors, but their clinical significance in gastric cancer (GC) remains unclear. This study aimed to investigate the prognostic significance of tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs).

Methods

Using a prospective database containing 401 cases of GC, we evaluated TIL (cluster of differentiation 8 (CD8) expression) and TAM (cluster of differentiation 68 (CD68) expression) statuses via immunohistochemical staining.

Results

Compared with CD8+ TIL-negative cases (n = 196, 48.6%), CD8+ TIL-positive cases (n = 205, 51.1%) showed significantly better recurrence-free survival (RFS) [log-rank p<0.001; multivariate HR: 0.372; 95% confidence interval (CI): 0.239–0.579, p<0.001]. In contrast, compared with CD68+ TAM-negative cases (n = 217, 54.1%), CD68+ TAM-positive cases (n = 184, 45.9%) had significantly poor RFS [log-rank p<0.001; multivariate HR: 2.182; 95% CI: 1.435–3.318, p<0.001]. Thus, patients with a positive CD8+ TIL and negative CD68+ TAM status exhibited significantly increased RFS. Multivariate analysis demonstrated that CD8+ TILs and CD68+ TAMs may serve as independent prognostic markers for RFS. Incorporating CD8+ TIL and CD68+ TAM statuses into the AJCC TNM system generated a predictive model with better predictive accuracy for RFS. More importantly, patients with a positive TIL and negative TAM status showed a tendency of improved RFS after postoperative adjuvant chemotherapy (PAC). Similar results were obtained by overall survival (OS) analysis.

Conclusions

CD8+ TIL and CD68+ TAM statuses were identified as independent prognostic factors that may be integrated into the current TNM staging system to refine risk stratification and to better predict the survival benefit from PAC in patients with GC.

Trial registration

The current controlled trial was registered at ClinicalTrials.gov (ID: NCT02327481) on December 30, 2014.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6089-z) contains supplementary material, which is available to authorized users.

PD-1 Ligand Expression in Epithelial Thyroid Cancers: Potential Clinical Implications

The new immunotherapy targeting the programmed cell death 1 (PD-1) receptor and its cognate ligand PD-L1 has renewed hopes of eradicating the most difficult human cancers to treat. Among these, there are the poorly differentiated and anaplastic thyroid cancers, unresponsive to all the therapies currently in use. In the present review we will summarize information regarding the expression of PD-L1 in the different thyroid cancer histotypes, its correlation with clinicopathological features, and its potential prognostic value. Then, we will evaluate the available data indicating the PD-1/PD-L1 axis as a promising target for thyroid cancer therapy.

Development of a prognostic index based on an immunogenomic landscape analysis of papillary thyroid cancer

BACKGROUND

Papillary thyroid cancer (PTC) is the most common subtype of thyroid cancer, and inflammation relates significantly to its initiation and prognosis. Systematic exploration of the immunogenomic landscape therein to assist in PTC prognosis is therefore urgent. The Cancer Genome Atlas (TCGA) project provides a large number of genetic PTC samples that enable a comprehensive and reliable immunogenomic study.

METHODS

We integrated the expression profiles of immune-related genes (IRGs) and progression-free intervals (PFIs) in survival in 493 PTC patients based on the TCGA dataset. Differentially-expressed and survival-associated IRGs in PTC patients were estimated a computational difference algorithm and COX regression analysis. The potential molecular mechanisms and properties of these PTC-specific IRGs were also explored with the help of computational biology. A new prognostic index based on immune-related genes was developed by using multivariable COX analysis.

RESULTS

A total of 46 differentially expressed immune-related genes were significantly correlated with clinical outcome of PTC patients. Functional enrichment analysis revealed that these genes were actively involved in a cytokine-cytokine receptor interaction KEGG pathway. A prognostic signature based on RGs (AGTR1, CTGF, FAM3B, IL11, IL17C, PTH2R and SPAG11A) performed moderately in prognostic predictions and correlated with age, tumor stage, metastasis, number of lesions, and tumor burden. Intriguingly, the prognostic index based on IRGs reflected infiltration by several types of immune cells.

CONCLUSIONS

Together, our results screened several IRGs of clinical significance, revealed drivers of the immune repertoire, and demonstrated the importance of a personalized, IRG-based immune signature in the recognition, surveillance, and prognosis of PTC.

Clinicopathologic and Prognostic Significance of Programmed Cell Death Ligand 1 Expression in Patients with Non-Medullary Thyroid Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence has shown that programmed cell death ligand 1 (PD-L1) overexpression is associated with poor prognosis and resistance to immune therapies in several human cancers. However, data on the prognostic significance of PD-L1 expression in thyroid cancer are limited and remain controversial. This systematic review and meta-analysis aimed to evaluate comprehensively the clinicopathologic significance and prognostic value of PD-L1 expression in non-medullary thyroid cancers.

METHODS

Electronic databases, including Medline/PubMed, EMBASE, and the Cochrane Library, were searched up until July 5, 2017. In total, seven comparisons (from six articles) comprising 1421 patients were included in the pooled analysis.

RESULTS

There was moderate quality evidence from four studies (n = 721) that shows positive PD-L1 expression was significantly associated with poor survival among thyroid cancer patients (pooled hazard ratio = 3.73 [confidence interval (CI) 2.75-5.06]). Increased PD-L1 expression was also found to be significantly associated with disease recurrence (odds ratio = 1.95 [CI 1.15-3.32]) and concurrent thyroiditis (odds ratio = 1.65 [CI 1.09-2.51]).

CONCLUSIONS

The results confirm the prognostic significance of PD-L1 expression in thyroid cancer patients. PD-L1 expression has the potential to be implemented as a prognostic biomarker used to guide clinicians in identifying patients with more aggressive cancers, and for the selection of individuals that would derive durable clinical benefit from anti-PD-1/PD-L1 immunotherapy. Prospective clinical trials will be useful to support these findings.