Exploring markers of immunoresponsiveness in papillary thyroid carcinoma and future treatment strategies.

BACKGROUND: The study summarizes the potential use of immunotherapy for BRAF-mutated papillary thyroid cancer (PTC) by analyzing the immune profile of City of Hope PTC patient samples and comparing them to the thyroid dataset available in the TCGA database. MATERIALS AND METHODS: PTC cases with available formalin-fixed paraffin-embedded archived tumor tissue were identified. RNA was extracted from the tumor tissue and analyzed by NanoString to evaluate their immune gene expression profile. Immunohistochemistry was used to determine the expression of immune suppressive genes and lymphocytic infiltration into the tumor tissue. Thyroid cancer cell lines (MDA-T32, MDA-T68, MDA-T85, and MDA-T120) were used to determine the correlation between the BRAF inhibition and CD274 expression. RESULTS: The study found that PTC cases with BRAF mutations had higher expression of immune checkpoint markers CD274 and CTLA4, as well as higher tumor-infiltrating lymphocytes, particularly CD4+T cells. Additionally, the study identified immunosuppressive markers expressed by tumor cells like CD73, CD276, and CD200 that could be targeted for immunotherapy. Further experiments using PTC cell lines lead to the conclusion that CD274 expression correlates with BRAF activity and that inhibitors of BRAF could potentially be used in combination with immunotherapy to treat PTC. CONCLUSIONS: These findings suggest that PTC cases with BRAF mutations or high expression may be correlated with an immune hot signature and could benefit from immunotherapeutic strategies.

The neurotransmitter calcitonin gene-related peptide shapes an immunosuppressive microenvironment in medullary thyroid cancer.

Neurotransmitters are key modulators in neuro-immune circuits and have been linked to tumor progression. Medullary thyroid cancer (MTC), an aggressive neuroendocrine tumor, expresses neurotransmitter calcitonin gene-related peptide (CGRP), is insensitive to chemo- and radiotherapies, and the effectiveness of immunotherapies remains unknown. Thus, a comprehensive analysis of the tumor microenvironment would facilitate effective therapies and provide evidence on CGRP's function outside the nervous system. Here, we compare the single-cell landscape of MTC and papillary thyroid cancer (PTC) and find that expression of CGRP in MTC is associated with dendritic cell (DC) abnormal development characterized by activation of cAMP related pathways and high levels of Kruppel Like Factor 2 (KLF2), correlated with an impaired activity of tumor infiltrating T cells. A CGRP receptor antagonist could offset CGRP detrimental impact on DC development in vitro. Our study provides insights of the MTC immunosuppressive microenvironment, and proposes CGRP receptor as a potential therapeutic target.

[Bioinformatic analysis of CCND2 expression in papillary thyroid carcinoma and its impact on immune infiltration].

OBJECTIVE: To investigate cyclin D2 (CCND2) expression in papillary thyroid carcinoma (PTC) and its association with the clinicopathological features. METHODS: The public databases TCGA, TIMER 2.0 and UALCAN were used to explore CCND2 expression level in PTC and adjacent tissues, and its diagnostic value for PTC was analyzed using ROC curves. GO enrichment analysis of CCND2-related differentially expressed genes (DEGs) in PTC was performed, and tumor immune infiltration of CCND2 in thyroid cancer was analyzed using TIMER database and CIBERSORT data source. RT-qPCR and Western blot were used to detect CCND2 expression in normal human thyroid cell line Nthy-ori-3-1 and human PTC cell lines TPC-1 and BCPAP. CCND2 expression was also detected in clinical specimens of PTC and adjacent tissues by immunohistochemistry, and its correlation with clinicopathological features of the patients were analyzed. RESULTS: Informatic analysis revealed significantly higher CCND2 mRNA expression in thyroid cancer than in the adjacent tissues (P < 0.001) in close correlation with tumor stage, gender, age, pathological subtype, and lymph node involvement (P < 0.05). ROC curve analysis showed that at the cutoff value of 4.983, the diagnostic sensitivity, specificity, and accuracy of CCND2 expression for PTC was 83.6%, 94.9%, and 78.5%, respectively. CCND2 expression was positively correlated with B cells, CD4+ T cells, and macrophages (P < 0.001) and negatively with CD8+ T cells (P < 0.01), and also correlated with memory B-cell infiltration, CD4+ T-cell memory activation, M2 macrophages, resting mast cells, and mast cell activation (P < 0.05). RT-qPCR, Western blot and immunohistochemistry showed significantly higher CCND2 expression in the PTC cells than in Nthy-ori-3-1 cells (P < 0.01) and also in clinical PTC tissues than in the adjacent tissues (P < 0.05) in correlation with tumor size, lymph node metastasis and TNM stage (P < 0.05). CONCLUSION: CCND2 overexpression is closely correlated with tumor progression and immune cell infiltration in PTC patients..

Analysis of lncRNA-miRNA-mRNA interactions identified a novel biomarker LINC00657 to improve prognosis prediction of papillary thyroid carcinoma.

BACKGROUND: Papillary thyroid cancer (PTC) is the most common type of thyroid cancer. Identification of novel biomarkers can potentially help explore the underlying molecular mechanisms of PTC. Long non-coding RNAs (lncRNAs) are involved in cancer development. However, understanding the role of lncRNA in PTC remains challenging. METHODS: Based on the competitive endogenous RNA (ceRNA) theory, we constructed a comprehensive PTC-related lncRNA-miRNA-mRNA network using data from The Cancer Genome Atlas. To evaluate the prognostic power, we performed survival analysis for patients with PTC with low and high lncRNA expression levels, and examined the relationship between lncRNA and immune-related functions. RESULTS: We identified a hub node, long intergenic non-coding RNA, LINC00657, as a novel prognostic biomarker in PTC. LINC00657 was differentially expressed between tumor and adjacent normal samples. Low LINC00657 expression levels was significantly associated with better survival outcome. Our functional analyses showed that LINC00657 was related with infiltration of CD8+ T cell and macrophage; immune check point molecules; and immune metagenes such as IgG, LCK, MHC_I/II and etc. These results suggest that LINC00657 is an immune-related biomarker with potential clinical applicability. Additionally, cancer-related signaling pathway and high frequency of gene BRAF mutation were found in PTC samples with high LINC00657 expression level, which were consistent with previous findings. CONCLUSION: LINC00657 is an immune-related biomarker that can potentially improve prognosis prediction in PTC. Our study provided new treatment target of PTC in clinical practice and offered the novel insights in elucidating the functional role of lncRNAs.

Interactions between LAMP3+ dendritic cells and T-cell subpopulations promote immune evasion in papillary thyroid carcinoma.

BACKGROUND: The incidence of papillary thyroid cancer (PTC) continues to rise all over the world, 10-15% of the patients have a poor prognosis. Although immunotherapy has been applied in clinical practice, its therapeutic efficacy remains far from satisfactory, necessitating further investigation of the mechanism of PTC immune remodeling and exploration of novel treatment targets. METHODS: This study conducted a single-cell RNA sequencing (scRNA-seq) analysis using 18 surgical tissue specimens procured from 14 patients diagnosed with adjacent tissues, non-progressive PTC or progressive PTC. Key findings were authenticated through spatial transcriptomics RNA sequencing, immunohistochemistry, multiplex immunohistochemistry, and an independent bulk RNA-seq data set containing 502 samples. RESULTS: A total of 151,238 individual cells derived from 18 adjacent tissues, non-progressive PTC and progressive PTC specimens underwent scRNA-seq analysis. We found that progressive PTC exhibits the following characteristics: a significant decrease in overall immune cells, enhanced immune evasion of tumor cells, and disrupted antigen presentation function. Moreover, we identified a subpopulation of lysosomal associated membrane protein 3 (LAMP3+) dendritic cells (DCs) exhibiting heightened infiltration in progressive PTC and associated with advanced T stage and poor prognosis of PTC. LAMP3+ DCs promote CD8+ T cells exhaustion (mediated by NECTIN2-TIGIT) and increase infiltration abundance of regulatory T cells (mediated by chemokine (C-C motif) ligand 17 (CCL17)-chemokine (C-C motif) receptor 4 (CCR4)) establishing an immune-suppressive microenvironment. Ultimately, we unveiled that progressive PTC tumor cells facilitate the retention of LAMP3+ DCs within the tumor microenvironment through NECTIN3-NECTIN2 interactions, thereby rendering tumor cells more susceptible to immune evasion. CONCLUSION: Our findings expound valuable insights into the role of the interaction between LAMP3+ DCs and T-cell subpopulations and offer new and effective ideas and strategies for immunotherapy in patients with progressive PTC.

Utilizing Immunoglobulin G4 Immunohistochemistry for Risk Stratification in Patients with Papillary Thyroid Carcinoma Associated with Hashimoto Thyroiditis.

BACKGRUOUND: Hashimoto thyroiditis (HT) is suspected to correlate with papillary thyroid carcinoma (PTC) development. While some HT cases exhibit histologic features of immunoglobulin G4 (IgG4)-related disease, the relationship of HT with PTC progression remains unestablished. METHODS: This cross-sectional study included 426 adult patients with PTC (≥1 cm) undergoing thyroidectomy at an academic thyroid center. HT was identified based on its typical histologic features. IgG4 and IgG immunohistochemistry were performed. Wholeslide images of immunostained slides were digitalized. Positive plasma cells per 2 mm2 were counted using QuPath and a pre-trained deep learning model. The primary outcome was tumor structural recurrence post-surgery. RESULTS: Among the 426 PTC patients, 79 were diagnosed with HT. With a 40% IgG4 positive/IgG plasma cell ratio as the threshold for diagnosing IgG4-related disease, a cutoff value of >150 IgG4 positive plasma cells per 2 mm2 was established. According to this criterion, 53% (43/79) of HT patients were classified as IgG4-related. The IgG4-related HT subgroup presented a more advanced cancer stage than the IgG4-non-related HT group (P=0.038). The median observation period was 109 months (range, 6 to 142). Initial assessment revealed 43 recurrence cases. Recurrence-free survival periods showed significant (P=0.023) differences, with patients with IgG4 non-related HT showing the longest period, followed by patients without HT and those with IgG4-related HT. CONCLUSION: This study effectively stratified recurrence risk in PTC patients based on HT status and IgG4-related subtypes. These findings may contribute to better-informed treatment decisions and patient care strategies.

Next-generation sequencing identified that RET variation associates with lymph node metastasis and the immune microenvironment in thyroid papillary carcinoma.

BACKGROUND: To date, although most thyroid carcinoma (THCA) achieves an excellent prognosis, some patients experience a rapid progression episode, even with differentiated THCA. Nodal metastasis is an unfavorable predictor. Exploring the underlying mechanism may bring a deep insight into THCA. METHODS: A total of 108 THCA from Chinese patients with next-generation sequencing (NGS) were recruited. It was used to explore the gene alteration spectrum of THCA and identify gene alterations related to nodal metastasis in papillary thyroid carcinoma (PTC). The Cancer Genome Atlas THCA cohort was further studied to elucidate the relationship between specific gene alterations and tumor microenvironment. A pathway enrichment analysis was used to explore the underlying mechanism. RESULTS: Gene alteration was frequent in THCA. BRAF, RET, POLE, ATM, and BRCA1 were the five most common altered genes. RET variation was positively related to nodal metastasis in PTC. RET variation is associated with immune cell infiltration levels, including CD8 naïve, CD4 T and CD8 T cells, etc. Moreover, Step 3 and Step 4 of the cancer immunity cycle (CIC) were activated, whereas Step 6 was suppressed in PTC with RET variation. A pathway enrichment analysis showed that RET variation was associated with several immune-related pathways. CONCLUSION: RET variation is positively related to nodal metastasis in Chinese PTC, and anti-tumor immune response may play a role in nodal metastasis triggered by RET variation.

Thyroglobulin Antibodies and Tumor Epitope-Specific Cellular Immunity in Papillary Thyroid Cancer.

Papillary thyroid carcinoma (PTC) is characterized by T cell infiltration and frequently by the presence of anti-thyroglobulin antibodies (TgAbs). The role of cellular immunity and of TbAbs in this context is a matter of debate. The aim of our study was to correlate the presence of TgAbs, tumor epitope-specific T cells and the clinical outcome of PTC patients. We studied n=183 consecutive patients with a diagnosis of PTC which were treated with total thyroidectomy plus 131I ablation. During a follow-up of in mean 97 months, most of the PTC patients had no signs of tumor relapse (n=157 patients). In contrast, one patient had serum Tg levels above the detection limit and<1 ng/ml, two patients Tg serum levels≥1 ng/ml and<2 ng/ml and n=23 patients had Tg serum levels≥2 ng/ml. Morphological signs of tumor recurrence were seen in 14 patients; all of these patients had serum Tg levels≥2 ng/ml. Importantly, with the exception of one patient, all TgAb positive PTC patients (n=27) had no signs of tumor recurrence as the serum Tg levels were below the assays functional sensitivities. Tetramer analyses revealed a higher number of tumor epitope-specific CD8+T cells in TgAb positive patients compared to TgAb negative PTC patients. In summary, we show that the occurrence of TgAbs may have an impact on the clinical outcome in PTC patients. This might be due to a tumor epitope-specific cellular immunity in PTC patients.

VDR is a potential prognostic biomarker and positively correlated with immune infiltration: a comprehensive pan-cancer analysis with experimental verification.

The vitamin D receptor (VDR) is a transcription factor that mediates a variety of biological functions of 1,25-dihydroxyvitamin D3. Although there is growing evidence of cytological and animal studies supporting the suppressive role of VDR in cancers, the conclusion is still controversial in human cancers and no systematic pan-cancer analysis of VDR is available. We explored the relationships between VDR expression and prognosis, immune infiltration, tumor microenvironment, or gene set enrichment analysis (GSEA) in 33 types of human cancers based on multiple public databases and R software. Meanwhile, the expression and role of VDR were experimentally validated in papillary thyroid cancer (PTC). VDR expression decreased in 8 types and increased in 12 types of cancer compared with normal tissues. Increased expression of VDR was associated with either good or poor prognosis in 13 cancer types. VDR expression was positively correlated with the infiltration of cancer-associated fibroblasts, macrophages, or neutrophils in 20, 12, and 10 cancer types respectively and this correlation was experimentally validated in PTC. Increased VDR expression was associated with increased percentage of stromal or immune components in tumor microenvironment (TME) in 24 cancer types. VDR positively and negatively correlated genes were enriched in immune cell function and energy metabolism pathways, respectively, in the top 9 highly lethal tumors. Additionally, VDR expression was increased in PTC and inhibited cell proliferation and migration. In conclusion, VDR is a potential prognostic biomarker and positively correlated with immune infiltration as well as stromal or immune components in TME in multiple human cancers.

A distinct tumor microenvironment makes anaplastic thyroid cancer more lethal but immunotherapy sensitive than papillary thyroid cancer.

Both anaplastic thyroid cancer (ATC) and papillary thyroid cancer (PTC) originate from thyroid follicular epithelial cells, but ATC has a significantly worse prognosis and shows resistance to conventional therapies. However, clinical trials found that immunotherapy works better in ATC than late-stage PTC. Here, we used single-cell RNA sequencing (scRNA-Seq) to generate a single-cell atlas of thyroid cancer. Differences in ATC and PTC tumor microenvironment components (including malignant cells, stromal cells, and immune cells) leading to the polarized prognoses were identified. Intriguingly, we found that CXCL13+ T lymphocytes were enriched in ATC samples and might promote the development of early tertiary lymphoid structure (TLS). Last, murine experiments and scRNA-Seq analysis of a treated patient's tumor demonstrated that famitinib plus anti-PD-1 antibody could advance TLS in thyroid cancer. We displayed the cellular landscape of ATC and PTC, finding that CXCL13+ T cells and early TLS might make ATC more sensitive to immunotherapy.

Single-cell RNA-seq reveals MIF-(CD74 + CXCR4) dependent inhibition of macrophages in metastatic papillary thyroid carcinoma.

BACKGROUND: The mechanism promoting papillary thyroid carcinoma (PTC) metastasis remains unclear. We aimed to investigate the potential metastatic mechanisms at a single-cell resolution. METHODS: We performed single-cell RNA-seq (scRNA-seq) profiling of thyroid tumour (TT), adjacent normal thyroid (NT) and lymph node metastasized tumour (LN) from a young female with PTC. Validation of our results was conducted in 31 tumours with metastasis and 30 without metastasis. RESULTS: ScRNA-seq analysis generated data on 38,215 genes and 0.14 billion transcripts from 28,839 cells, classified into 18 clusters, each annotated to represent 10 cell types. PTC cells were found to originate from epithelial cells. Epithelial cells and macrophages emerged as the strongest signal emitters and receivers, respectively. After reclustering epithelial cells and macrophages, our analysis, incorporating gene set variation analysis (GSVA), SCENIC analysis, and pseudotime trajectory analysis, indicated that subcluster 0 of epithelial cells (EP_0) showed a more malignant phenotype, and subclusters 3 and 4 of macrophages (M_3 and M_4) demonstrated heightened activity. Further analysis suggested that EP_0 may suppress the activity of M_3 and M_4 via MIF - (CD74 + CXCR4) in the MIF pathway. After analysing the expression of the 4 genes in the MIF pathway in both the TCGA cohort and our cohort (n = 61), CD74 was identified as significantly overexpressed in PTC tumours particularly those with lymph node metastasis. CONCLUSION: Our study revealed that PTC may facilitate lymph node metastasis by inhibiting macrophages via MIF signalling. It is suggested that malignant PTC cells may suppress the immune activity of macrophages by consistently releasing signals to them via MIF-(CD74 + CXCR4).

BRAFV600E and BRAF-WT Specific Antitumor Immunity in Papillary Thyroid Cancer.

One feature of papillary thyroid cancer (PTC) is the frequently present somatic BRAFV600E mutation. PTCs are also characterized by a lymphocytic infiltration, which may correlate with an improved clinical outcome. The objective of the study was the characterization of BRAFV600E specific anti-immunity in PTC patients and correlation analyses with the clinical outcome. Fourteen HLA A2 positive PTC patients were included into the study of whom tumor tissue samples were also available. Of those, 8 PTC patients revealed a somatic BRAFV600E mutation. All PTC patients were also MHC class II typed. Tetramer analyses for detection of MHC class I and MHC class II-restricted, BRAFV600E epitope-specific T cells using unstimulated and peptide-stimulated T cells were performed; correlation analyses between MHC phenotypes, T cell immunity, and the clinical course were performed. In regard to unstimulated T cells, a significantly higher amount of BRAFV600E epitope specific T cells was detected compared to a control tetramer. Importantly, after overnight peptide stimulation a significantly higher number of BRAFV600E positive and BRAF WT epitope-specific T cells could be seen. In regard to the clinical course, however, no significant differences were seen, neither in the context of the initial tumor size, nor in the context of lymph node metastases or peripheral metastastic spread. In conclusion, we clearly demonstrated a BRAF-specific tumor immunity in PTC-patients which is, however, independent of a BRAFV600E status of the PTC patients.

Low expression of TFF3 in papillary thyroid carcinoma may correlate with poor prognosis but high immune cell infiltration.

Background: Papillary thyroid carcinoma (PTC) is one of the most common endocrine malignancies and has a favorable prognosis. However, optimal treatments and prognostic markers have not been clearly identified. Methods: Gene expression data from primary PTC were downloaded from the Gene Expression Omnibus database and subjected to two analyses of differentially expressed genes (DEGs), followed by intersecting individual and integrated DEGs analyses as well as gene set enrichment analysis. Analysis of data from Sequence Read Archive and The Cancer Genome Atlas, immunohistochemistry and qRT-PCR of TFF3 were performed to validate the results. Finally, the relationship between gene expression and disease-free survival as well as immune cell infiltration were investigated. Results: Six critical DEGs and several tumor-enriched signaling pathways were identified. Immunohistochemistry and qRT-PCR validated the low expression of TFF3 in PTC. TFF3 and FCGBP are coexpressed in PTC, and patients with lower gene expression had worse disease-free survival but higher immune cell infiltration. Conclusion: TFF3 was significantly underexpressed and may function with FCGBP synergistically in PTC.

Lay abstract Thyroid cancers are some of the most common endocrine malignancies. However, the optimal treatments and prognostic markers have not been clearly identified. We identified six critical differentially expressed genes and several tumor-enriched signaling pathways in papillary thyroid carcinoma, and found that TFF3 was the most underexpressed gene, as validated by experiment. In addition, TFF3 and FCGBP worked synergistically and may mark prognosis and tumor immune cell infiltration, which may benefit patients with papillary thyroid carcinoma by providing early indication and prompting further basic investigation.

Proteomics and Organoid Culture Reveal the Underlying Pathogenesis of Hashimoto's Thyroiditis.

Hashimoto's thyroiditis (HT) is an autoimmune disease, and its incidence continues to rise. Although scientists have studied this disease for many years and discovered the potential effects of various proteins in it, the specific pathogenesis is still not fully comprehended. To understand HT and translate this knowledge to clinical applications, we took the mass spectrometric analysis on thyroid tissue fine-needle puncture from HT patients and healthy people in an attempt to make a further understanding of the pathogenesis of HT. A total of 44 proteins with differential expression were identified in HT patients, and these proteins play vital roles in cell adhesion, cell metabolism, and thyroxine synthesis. Combining patient clinical trial sample information, we further compared the transient changes of gene expression regulation in HT and papillary thyroid carcinoma (PTC) samples. More importantly, we developed patient-derived HT and PTC organoids as a promising new preclinical model to verify these potential markers. Our data revealed a marked characteristic of HT organoid in upregulating chemokines that include C-C motif chemokine ligand (CCL) 2 and CCL3, which play a key role in the pathogenesis of HT. Overall, our research has enriched everyone's understanding of the pathogenesis of HT and provides a certain reference for the treatment of the disease.

ANXA1 (Annexin A1) regulated by MYC (MYC proto-oncogene) promotes the growth of papillary thyroid carcinoma.

Thyroid carcinoma is one of the most common endocrine malignancies, in which papillary thyroid carcinoma (PTC) is the main pathotype. ANXA1 plays a significant role in many cancer types, but how it works in PTC has not been identified. MYC is a common transcript factor involved in tumorigenesis, development, invasion, and metastasis. The relation between ANXA1 and MYC has not been proved in PTC. In this study, firstly, we analyzed the expression and prognostic value of ANXA1 in pan-cancer using the data from the UCSC database. Then we explore the role of ANXA1 in PTC, including expression, prognostic value, and immune infiltration. In addition, we evaluated the relation between ANXA1 and the transcription factor MYC. Finally, we identified the expression of ANXA1 and MYC and then evaluated their function associated with proliferation and apoptosis in PTC cell lines by CCK8 proliferation and flow cytometry apoptosis experiment. We found that ANXA1 is up-regulated in PTC comparing with normal patients. High expression of ANXA1 was associated with adverse overall survival of PTC. ANXA1 may be regulated by MYC to promote the proliferation of PTC. MYC may regulate the expression of ANXA and thus affect the proliferation of PTC.

Development and validation of a ferroptosis-related prognostic model for the prediction of progression-free survival and immune microenvironment in patients with papillary thyroid carcinoma.

BACKGROUND: Ferroptosis is an iron-dependent and regulated cell death that has been widely reported in a variety of malignancies. The overall survival of papillary thyroid cancer (PTC) is excellent, but the identification of patients with poor prognosis still faces challenges. Nevertheless, whether ferroptosis-related genes (FRGs) can be used to screen high-risk patients is not clear. METHODS: We obtained the clinical data of patients with PTC and FRGs from the UCSC Xena platform and the FerrDb respectively. Differentially expressed genes (DEGs) of FRGs were obtained from the entire The Cancer Genome Atlas (TCGA). Subsequently, the entire TCGA dataset was randomly split into two subsets: training and test datasets. Based on DEGs, we constructed a predictive model which was tested in the test dataset and the entire TCGA dataset to predict progression-free survival (PFS). Patients were categorized into high- or low-risk groups based on their median risk score. We analyzed differences in some aspects, including pathway enrichment analysis, single-sample Gene Set Enrichment Analysis (ssGSEA), tumor microenvironment (TME), human leukocyte antigen (HLA) genes, and tumor mutation burden (TMB) analyses, between high-risk and low-risk groups. RESULTS: A predictive model with three FRGs (HSPA5, AURKA, and TSC22D3) was constructed. Patients in the high-risk group had worse PFS compared with patients in the low-risk group. Functional analysis results revealed that ssGSEA, immune cell infiltration, TME, HLA, and TMB were closely associated with ferroptosis. CONCLUSION: The prognostic model constructed in this study can effectively predict PFS for patients with PTC.

T cell exhaustion is associated with the risk of papillary thyroid carcinoma and can be a predictive and sensitive biomarker for diagnosis.

BACKGROUND: The incidence of papillary thyroid carcinoma (PTC) has been steadily increasing over the past decades. Hashimoto's thyroiditis (HT) is the most common autoimmune disease, and is related to the pathogenesis of PTC. Programmed death-1 (PD-1) is currently used for the treatment of PTC, but there are very few studies on the clinical value of PD-1 in the diagnosis and targeted therapy of PTC. METHODS: The expression of T, B, NK cells and PD-1 in the peripheral blood of 132 patients with PTC (PTC group), 48 patients with nodular goiter (NG group) and 63 healthy subjects (HP group) were detected by flow cytometry. The expression of plasma T3, T4, FT3, FT4, TSH, TGAb and TPO was detected by chemiluminescence immunoassay. Among 132 PTC, 49 PTC&HT and 83 PTC&noHT were included. Among 48 NG, 10 NG&HT and 38 NG&noHT were included. The expressions of programmed death- ligand1(PD-L1) in tumor tissues of PTC group and thyroid tissues of NG group, PD-1 and CD3 in tumor infiltration lymphocyte (TIL) were detected by immunohistochemistry. RESULTS: The expression of FT3, TGAb, CD3+PD-1+, CD3+CD4+PD-1+ and CD3+CD8+PD-1+ in PTC and NG was significantly higher than that in the HP group. Moreover, CD3+PD-1+, CD3+CD4+PD-1+ and CD3+CD8+PD-1+ expression had significant differences between the PTC group and the NG group. In addition, the expression of TGAb, TPO, CD3+PD-1+, CD3+CD4+PD-1+ and CD3+CD8+PD-1+ in PTC&HT group was significantly higher than that in the PTC&noHT group. While, the expression of B cells, CD3+PD-1+, CD3+CD4+PD-1+ and CD3+CD8+PD-1+ in PTC&HT group was higher than that in NG&HT group. PD-1 showed a significant correlation with PTC lymph node metastasis. CD3+PD-1+ and CD3+CD4+PD-1+ was higher in N1 stage than in N0 stage. Immunohistochemical results showed that the expression of PD-1, CD3 and PD-L1 in PTC was significantly higher than that in NG. CONCLUSIONS: T cell exhaustion might act as a biomarker for the differential diagnosis of PTC and NG. Patients with PTC&HT have obvious T cell exhaustion and increased expression of PD-1, PD-L1.Targeting the PD-1/PD-L1 pathway could be a new approach to prevent malignant transformation from HT to PTC&HT in the future.

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.

Prevalence of Hashimoto Thyroiditis in Adults With Papillary Thyroid Cancer and Its Association With Cancer Recurrence and Outcomes.

Importance: Hashimoto thyroiditis (HT) has been suggested to be associated with papillary thyroid cancer (PTC) development. However, its association with PTC progression remains unclear. Objective: To examine the association between HT and PTC presentation and outcomes. Design, Setting, and Participants: This retrospective cohort study included a review of patients aged 18 to 75 years who had pathologically confirmed PTC treated at a single center in China from January 1, 2001, to December 31, 2014. Data analysis was performed from November 1 to December 31, 2020. Exposures: Coexistent HT was defined according to evaluation of postoperative paraffin sections. Main Outcomes and Measures: The primary outcome was the association of HT with PTC-related mortality, assessed using Cox proportional hazards regression models. The secondary outcome was the association of HT with aggressive characteristics and structural recurrence of PTC, assessed using logistic regression and Cox proportional hazards regression with and without adjustment for related factors. Results: Of 9210 patients with PTC (mean [SD] age, 43.6 [12.0] years; 6872 [75%] women) included in the analysis, 1751 (19%) had HT. In the logistic regression model, HT was negatively associated with frequencies of primary tumor size of 4 cm or greater (adjusted odds ratio [aOR], 0.20; 95% CI, 0.12-0.33; P < .001), gross extrathyroidal extension (aOR, 0.44; 95% CI, 0.36-0.54; P < .001), extranodal extension (aOR, 0.66; 95% CI, 0.55-0.80; P < .001), and distant metastasis (aOR, 0.17; 95% CI, 0.04-0.71; P = .02). After a median follow-up of 85 months (range, 12-144 months), 131 PTC-related deaths were identified in the cohort; 2 patients who died had HT. Patients with HT had significantly superior outcomes compared with patients without HT in terms of unadjusted 10-year disease-specific survival (99.9% vs 96.6%; log-rank P < .001) and recurrence-free survival (92.0% vs 87.6%; log-rank P = .001). After adjusting for sex, age, primary tumor size, extrathyroidal extension, lymph node metastasis, distant metastasis, extent of surgery, and radioactive iodine ablation, HT was associated with decreased PTC-related mortality (hazard ratio [HR], 0.19; 95% CI, 0.05-0.76; P = .02). Stratified analysis showed that HT was associated with less frequent structural recurrence in patients with extrathyroidal extension (HR, 0.52; 95% CI, 0.38-0.71; P < .001; P = .002 for interaction) or after total thyroidectomy (HR, 0.50; 95% CI, 0.35-0.69; P < .001; P = .009 for interaction). Conclusions and Relevance: In this cohort study, patients with coexistent HT had less aggressive characteristics at presentation and better outcomes of PTC than did patients without HT. The findings suggest that autoimmune thyroiditis has a protective role in association with thyroid cancer.

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 CD56bright 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.