B cells and tertiary lymphoid structures are associated with survival in papillary thyroid cancer

Single-cell transcriptomics analysis reveals that the tumor-infiltrating B cells determine the indolent fate of papillary thyroid carcinoma

OBJECTIVE

Active surveillance (AS) offers a viable alternative to surgical intervention for the management of indolent papillary thyroid carcinoma (PTC), helping to minimize the incidence of unnecessary treatment. However, the broader adoption of AS is hindered by the need for more reliable diagnostic markers. This study aimed to identify the differences between indolent and progressive PTC and find new targets for biomarker development and therapeutic strategies.

METHODS

We used single-cell RNA sequencing (scRNA-seq) to analyze cellular differences in 10 early-stage PTC tumors. Findings were validated in an additional 25 tumors using cell co-culture, migration assays, immunofluorescence staining, flow cytometry, and analysis of data from The Cancer Genome Atlas (TCGA).

RESULTS

Tumor-infiltrating B cells (TIL-B), particularly germinal center B cells (GC-B), were more abundant in indolent PTC. These cells suppressed thyroid cell proliferation in both indolent and progressive cases, though indolent PTC had a higher capacity to recruit peripheral B cells. In indolent cases, TIL-B cells showed increased proliferation and formed clusters within tertiary lymphoid structures (TLS). PTPRC-CD22 interactions were identified as potential drivers of TIL-B cell proliferation. Markers linked to GC-B cells, such as LMO2, were highlighted as potential diagnostic and prognostic indicators for indolent PTC.

CONCLUSION

This study provides insights into the cellular landscape of early-stage PTC, revealing distinct tumor and immune microenvironment features in indolent and progressive cases. These findings advance the understanding of indolent PTC biology and support the development of reliable diagnostic and prognostic biomarkers.

IgG4-mediated M2 macrophage polarization in tertiary lymphoid structures of esophageal cancer: implications for immunosuppression

Background

Our previous research highlighted the potential role of immunoglobulin G4 (IgG4) in mediating immunosuppression within the tumor microenvironment (TME). Tertiary lymphoid structures (TLS) in the TME have important immune-related functions. This study aims to analyze the distribution characteristics of IgG4-expressing cells, regulatory T cells (Tregs), and M2-type macrophages as well as to elucidate the relationship between IgG4 and the polarization of M2 macrophages within TLS in esophageal cancer.

Object

To elucidate the distribution of IgG4, Treg cells, and M2 macrophages in TLS and to assess the impact of IgG4 on macrophage polarization.

Methods

Esophageal cancer tissue were analyzed with multiplex immunofluorescence to determine the spatial distribution and density of B cells, T cells, and their subtypes. The relationship between IgG4 and CD8+ T cells in TLS, along with interleukin-10 (IL-10) expression and Treg presence, was studied. Serum IgG4 and IL-10 levels were compared between patients and healthy controls. In vitro, the impact of IgG4 on monocyte differentiation into M2 macrophages was observed.

Results

IgG4 density was inversely related with CD8+ T cells in mature TLS indicating a potential immunosuppressive role (P<0.05,*). Serum analysis revealed that both IgG4 (P<0.01, **) and IL-10 (P<0.0001, ****) were significantly elevated and positively correlated in tumor patients compared to controls (P<0.01, **). In vitro experiments confirmed that IgG4 monocyte differentiation into M2 macrophages, potentially enhancing the immunosuppressive phenotype in TLS.

Conclusion

IgG4 and IL-10 may contribute to immunosuppression in esophageal cancer by promoting the polarization of M2 macrophages within TLS, which could be a therapeutic target.

Machine Vision-Detected Peritumoral Lymphocytic Aggregates Are Associated With Disease-Free Survival in Patients With Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) is the most prevalent form of thyroid cancer, with a disease recurrence rate of around 20%. Lymphoid formations, which occur in nonlymphoid tissues during chronic inflammatory, infectious, and immune responses, have been linked with tumor suppression. Lymphoid aggregates potentially enhance the body's antitumor response, offering an avenue for attracting tumor-infiltrating lymphocytes and fostering their coordination. Increasing evidence highlights the role of lymphoid aggregate density in managing tumor invasion and metastasis, with a favorable impact noted on overall and disease-free survival (DFS) across various cancer types. In this study, we present a machine vision model to predict recurrence in different histologic subtypes of PTC using measurements related to peritumoral lymphoid aggregate density. We demonstrated that quantifying peritumoral lymphocytic presence not only is associated with better prognosis but also, along with tumor-infiltrating lymphocytes within the tumor, adds additional prognostic value in the absence of well-known second mutations including TERT. Annotations of peritumoral lymphoid aggregates on 171 well-differentiated PTCs in the Cancer Genome Atlas Thyroid Carcinoma (TCGA-THCA) data set were used to train a deep-learning model to predict regions of lymphoid aggregates across the entire tissue. The fractional area of the tissue regions covered by these lymphocytes was dichotomized to determine the following 2 risk groups: a significant and low density of peritumoral lymphocytes. DFS prognosticated using these risk groups via the Kaplan-Meier analysis revealed a hazard ratio (HR) of 2.51 (95% CI: 2.36, 2.66), tested on 170 new patients also from the TCGA-THCA data set. The prognostic performance of peritumoral lymphocyte aggregate density was compared against the univariate Kaplan-Meier analysis of DFS using the fractional area of intratumoral lymphocytes within the primary tumor with an HR of 2.04 (95% CI: 1.89, 2.19). Combining the lymphocyte features in and around the tumor yielded a statistically significant improvement in prognostic performance (HR, 3.17 [95% CI: 3.02, 3.32]) on training and were independently evaluated against 62 patients outside TCGA-THCA with an HR of 2.44 (95% CI: 2.19, 2.69). Multivariable Cox regression analysis on the validation set revealed that the density of peritumoral and intratumoral lymphocytes was prognostic independent of histologic subtype with a concordance index of 0.815.

Harnessing Immunity to Treat Advanced Thyroid Cancer

The incidence of thyroid cancer (TC) has increased over the past 30 years. Although differentiated thyroid cancer (DTC) has a good prognosis in most patients undergoing total thyroidectomy followed by radioiodine therapy (RAI), 5-10% of patients develop metastasis. Anaplastic thyroid cancer (ATC) has a low survival rate and few effective treatments have been available to date. Recently, tyrosine kinase inhibitors (TKIs) have been successfully applied to RAI-resistant or non-responsive TC to suppress the disease. However, TC eventually develops resistance to TKIs. Immunotherapy is a promising treatment for TC, the majority of which is considered an immune-hot malignancy. Immune suppression by TC cells and immune-suppressing cells, including tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells, is complex and dynamic. Negative immune checkpoints, cytokines, vascular endothelial growth factors (VEGF), and indoleamine 2,3-dioxygenase 1 (IDO1) suppress antitumor T cells. Basic and translational advances in immune checkpoint inhibitors (ICIs), molecule-targeted therapy, tumor-specific immunotherapy, and their combinations have enabled us to overcome immune suppression and activate antitumor immune cells. This review summarizes current findings regarding the immune microenvironment, immunosuppression, immunological targets, and immunotherapy for TC and highlights the potential efficacy of immunotherapy.