Intra-tumoral and peripheral blood TIGIT and PD-1 as immune biomarkers in nodular lymphocyte predominant Hodgkin lymphoma.

In classical Hodgkin lymphoma (cHL), responsiveness to immune-checkpoint blockade (ICB) is associated with specific tumor microenvironment (TME) and peripheral blood features. The role of ICB in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is not established. To gain insights into its potential in NLPHL, we compared TME and peripheral blood signatures between HLs using an integrative multiomic analysis. A discovery/validation approach in 121 NLPHL and 114 cHL patients highlighted >2-fold enrichment in programmed cell death-1 (PD-1) and T-cell Ig and ITIM domain (TIGIT) gene expression for NLPHL versus cHL. Multiplex imaging showed marked increase in intra-tumoral protein expression of PD-1+ (and/or TIGIT+) CD4+ T-cells and PD-1+CD8+ T-cells in NLPHL compared to cHL. This included T-cells that rosetted with lymphocyte predominant (LP) and Hodgkin Reed-Sternberg (HRS) cells. In NLPHL, intra-tumoral PD-1+CD4+ T-cells frequently expressed TCF-1, a marker of heightened T-cell response to ICB. The peripheral blood signatures between HLs were also distinct, with higher levels of PD-1+TIGIT+ in TH1, TH2, and regulatory CD4+ T-cells in NLPHL versus cHL. Circulating PD-1+CD4+ had high levels of TCF-1. Notably, in both lymphomas, highly expanded populations of clonal TIGIT+PD-1+CD4+ and TIGIT+PD-1+CD8+ T-cells in the blood were also present in the TME, indicating that immune-checkpoint expressing T-cells circulated between intra-tumoral and blood compartments. In in vitro assays, ICB was capable of reducing rosette formation around LP and HRS cells, suggesting that disruption of rosetting may be a mechanism of action of ICB in HL. Overall, results indicate that further evaluation of ICB is warranted in NLPHL.

Delineating the breast cancer immune microenvironment in the era of multiplex immunohistochemistry/immunofluorescence.

Breast cancer is the most common malignancy and the leading cause of cancer death in females worldwide. Treatment is challenging, especially for those who are triple-negative. Increasing evidence suggests that diverse immune populations are present in the breast tumour microenvironment, which opens up avenues for personalised drug targets. Historically, our investigations into the immune constitution of breast tumours have been restricted to analyses of one or two markers at a given time. Recent technological advances have allowed simultaneous labelling of more than 35 markers and detailed profiling of tumour-immune infiltrates at the single-cell level, as well as determining the cellular composition and spatial analysis of the entire tumour architecture. In this review, we describe emerging technologies that have contributed to the field of breast cancer diagnosis, and discuss how to interpret the vast data sets obtained in order to effectively translate them for clinically relevant use.

Genetic aberrations of NLRC5 are associated with downregulated MHC-I antigen presentation and impaired T-cell immunity in follicular lymphoma.

Follicular lymphoma (FL) is the most common indolent non-Hodgkin lymphoma. Twenty to twenty-five percent of FL patients have progression of disease within 24 months. These patients may benefit from immunotherapy if intact antigen presentation is present. Molecular mechanisms impairing major histocompatibility complex class-I (MHC-I) in FL remain undefined. Here, by sequencing of 172 FL tumours, we found the MHC-I transactivator NLRC5 was the most frequent gene abnormality in the MHC-I pathway. Pyrosequencing showed that epigenetic silencing of the NLRC5 promoter occurred in 30% of cases and was mutually exclusive to copy number loss (CNL) in NLRC5 (∼6% of cases). Hypermethylation and CNLs ("NLRC5 aberrant") had reduced NLRC5 gene expression compared to wild-type (WT) cases. By NanoString, there was reduced gene expression of the MHC-I pathway in aberrant tissues, including immunoproteasome components (PSMB8 and PSMB9), peptide transporters of antigen processing (TAP1), and MHC-I (HLA-A), compared to WT. By immunofluorescent microscopy, fewer NLRC5 protein-expressing malignant B-cells were observed in NLRC5 aberrant tissue sections compared to NLRC5 WT (P < .01). Consistent with a pivotal role in the activation of CD8+ T-cells, both CD8 and CD137 strongly correlated with NLRC5 expression (both r > 0.7; P < .0001). Further studies are required to determine whether patients with aberrant NLRC5 have a diminished response to immunotherapy.