Intratumoral PD-1+CD8+ T cells associate poor clinical outcomes and adjuvant chemotherapeutic benefit in gastric cancer.

BACKGROUND: Although PD-1 has been reported to be a marker of T-cell exhaustion in several malignancies, the biological role of PD-1+CD8+ T cells in gastric cancer (GC) remains unclear. Herein, we aimed to investigate the role of PD-1+CD8+ T cells in the tumour microenvironment and its clinical significance in GC. DESIGNS: This study included 441 tumour microarray specimens and 60 Flow cytometry specimens of GC patients from Zhongshan Hospital, and 250 GC patients from the Asian Cancer Research Group. RESULTS: Here, we demonstrated that PD-1+CD8+ T cells functioned as an independent adverse prognosticator in GC. In addition, an abundance of intratumoral PD-1+CD8+ T cells indicated worse chemotherapeutic responsiveness to fluorouracil in Stage III GC patients. Mechanistically, PD-1+CD8+ T cell high infiltration indicated an exhausted phenotype of global CD8+ T cells in GC tissues, which was characterised by elevated immune checkpoint expression including CTLA-4 and TIM-3, whereas decreased expression of perforin. Furthermore, PD-1+CD8+ T cell high-infiltration patients with Stage III GC held elevated activity of several therapeutic signal pathways. CONCLUSIONS: Our study highlighted that PD-1+CD8+ T cell abundance predicts inferior prognosis in GC, and may serve as a novel predictive biomarker to guide therapeutic option.

Impact of intratumoural CD96 expression on clinical outcome and therapeutic benefit in gastric cancer.

CD96 was identified as a novel immune checkpoint. However, the role of CD96 in the gastric cancer (GC) microenvironment remains fragmentary. This study aimed to probe the clinical significance of CD96 to predict prognosis and therapeutic responsiveness, and to reveal the immune contexture and genomic features correlated to CD96 in GC patients. We enrolled 496 tumor microarray specimens of GC patients from Zhongshan Hospital (ZSHS) for immunohistochemical analyses. Four hundred and twelve GC patients from the Cancer Genome Atlas (TCGA) and 61 GC patients treated with pembrolizumab from ERP107734 published in the European Nucleotide Archive (ENA) were gathered for further analysis of the association between CD96+ cell infiltration and immune contexture, molecular characteristics, and genomic features by CIBERSORT and gene set enrichment analysis. Clinical outcomes were analyzed by Kaplan-Meier curves, the Cox model, interaction testing, and receiver operating characteristic analysis. High CD96+ cell infiltration predicted poor prognosis and inferior survival benefits from fluorouracil-based adjuvant chemotherapy in the ZSHS cohort whereas superior therapeutic responsiveness to pembrolizumab was shown in the ENA cohort. CD96-enriched tumors showed an immunosuppressive tumor microenvironment featured by exhausted CD8+ T-cell infiltration in both the ZSHS and TCGA cohorts. Moreover, in silico analysis for the TCGA cohort revealed that several biomarker-targeted pathways displayed significantly elevated enrichment levels in the CD96 high subgroup. This study elucidated that CD96 might drive an immunosuppressive contexture with CD8+ T-cell exhaustion and represent an independent adverse prognosticator in GC. CD96 could potentially be a novel biomarker for precision medicine of adjuvant chemotherapy, immunotherapy, and targeted therapies in GC.

Poor Clinical Outcomes and Immunoevasive Contexture in Intratumoral IL-10-Producing Macrophages Enriched Gastric Cancer Patients.

OBJECTIVE: To investigate the clinical significance of IL-10+ tumor-associated macrophages (TAMs) in gastric cancer. BACKGROUND: Due to the plasticity and diversity of TAMs, it is necessary to phenotypically and functionally classify subsets of TAMs to better understand the critical role of TAMs in cancer progression. TAMs expressing interleukin-10 (IL-10) have been found to facilitate immune evasion in many malignancies, but the role of IL-10+ TAMs in gastric cancer remains obscure. METHODS: Four hundred and sixty-eight tumor tissue microarray specimens, 52 fresh tumor tissue samples of gastric cancer patients from Zhongshan Hospital, and data of 298 gastric cancer patients from the Cancer Genome Atlas (TCGA) were analyzed. IL-10+ TAM level and immune contexture were examined by CIBERSORT, immunohistochemistry, and flow cytometry. Clinical outcomes were analyzed by Kaplan-Meier curves and Cox model. RESULTS: Gastric cancer patients with high IL-10+ TAM infiltration exhibited poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy. IL-10+ TAM infiltration yielded an immunoevasive tumor microenvironment featured by regulatory T cell infiltration and CD8+ T cell dysfunction. The combinational analysis of IL-10+ TAM and CD8+ T cell infiltration stratified patients into distinct risk groups with different clinical outcomes. Moreover, IL-10+ TAM infiltration was correlated with tumor-intrinsic characteristics including EBV status, PD-L1 expression, and genome stability in gastric cancer. CONCLUSIONS: This study revealed that IL-10+ TAMs might drive an immunoevasive microenvironment and determine poor prognosis and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy, indicating IL-10+ TAMs could be applied as a potential target for immunotherapeutic approach in gastric cancer.

Immune inactivation by APOBEC3B enrichment predicts response to chemotherapy and survival in gastric cancer.

Apolipoprotein B mRNA editing enzyme catalytic polypeptide 3B (APOBEC3B) plays an important role in tumor mutagenesis. However, its clinical significance in gastric cancer (GC) remains largely unknown. We enrolled a total of 482 GC patients from Zhongshan Hospital, Fudan University for immunohistochemistry (IHC) staining to evaluate the prognostic and predictive values of APOBEC3B. Genomic and phenotypic datasets from the Cancer Genome Atlas (TCGA) and Asian Cancer Research Group (ACRG) cohort were downloaded for external validation and complementary bioinformatic analysis. Fresh specimens of additional 60 patients from Zhongshan Hospital, Fudan University were collected to detect CD8+ T cell phenotype with flow cytometry (FCM). The high expression of APOBEC3B indicated inferior overall survival (OS, P < .001 and P = .003) and disease-free survival (DFS, P < .001 and P < .001), yet superior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy (ACT) in TNM stage II patients. The tumor microenvironment (TME) of APOBEC3B-enriched tumors was characterized by reduced infiltration of tumor reactive CD8+ T cells expressing both effector molecules and immune checkpoints. APOBEC3B high CD8+ T cell high GC patients were most likely to benefit from ACT and PD-1 blockade. Our study demonstrates that APOBEC3B was an independent prognostic and predictive factor in GC. The potential interplay between APOBEC3B and CD8+ T cells merited further investigations.

Poor clinical outcomes of intratumoral dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin-positive macrophages associated with immune evasion in gastric cancer.

AIM: Tumour-associated macrophages (TAMs) are prominent immune cells infiltrating in solid tumours with phenotypic and functional heterogeneity. However, the clinical significance of heterogeneous subtypes of TAMs in gastric cancer still remains obscure. Here, we aimed to explore the clinical significance of TAMs expressing dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and its relevance with immune contexture in gastric cancer. METHODS: We selected 453 formalin-fixed and paraffin-embedded samples and 51 fresh tissue specimens of patients with gastric cancer from Zhongshan Hospital. The association of DC-SIGN+ macrophages with clinicopathological parameters, overall survival (OS) and responsiveness to fluorouracil-based adjuvant chemotherapy (ACT) was inspected. Immunohistochemistry (IHC) and flow cytometry (FCM) were applied to characterize immune cells in gastric cancer. RESULTS: We demonstrated that high intratumoral DC-SIGN+ macrophages infiltration predicted poor OS and inferior therapeutic responsiveness to fluorouracil-based ACT in patients with gastric cancer. Furthermore, higher infiltration of DC-SIGN+ macrophages indicated an increased number of Foxp3+ regulatory T cells (Tregs), CD8+ T cells and a higher ratio of Foxp3+/CD8+ within the tumour microenvironment (TME). In addition, CD8+ T cells in DC-SIGN+ macrophages high subgroup were functionally impaired, showing decreased interferon-γ (IFN-γ), granzyme B (GZMB) and perforin production yet elevated programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression. CONCLUSIONS: DC-SIGN+ macrophages were associated with immunoinvasive TME and indicated poor prognosis and inferior therapeutic responsiveness to fluorouracil-based ACT. DC-SIGN+ macrophages might be an independent prognosticator and a potential immunotherapeutic target for gastric cancer.