CD3+, CD8+, CD4+ and FOXP3+ T Cells in the Immune Microenvironment of Small Bowel Neuroendocrine Tumors

Influence of PD-1/PD-L1 on immune microenvironment in oral leukoplakia and oral squamous cell carcinoma

OBJECTIVE

To evaluate the relation between the expression of PD-1, PD-L1, CD3, CD8, Foxp3 and clinicopathological features in patients with oral leukoplakia (OLK) and oral squamous cell carcinomas (OSCC) as well as the malignant outcome in OLK patients, and to study the effect of PD-1 and PD-L1 on immune microenvironment in the progression of oral carcinogenesis.

METHODS

We evaluated the expression of PD-1/PD-L1 and composition of CD3+ , CD8+ and Foxp3+ T lymphocytes in OLK and OSCC samples by immunohistochemical (IHC) staining and analyzed their relation with clinical information and malignant transformation in OLK patients.

RESULTS

IHC staining demonstrated that the expression of PD-1 was significantly increased in the high-grade OLK group than in the low-grade OLK group, while PD-L1 was detected mainly in OSCC. The expression of CD3, CD8, and Foxp3 was found higher in the high-grade OLK group than in the low-grade OLK group, and the Foxp3+ cells were found more in the OSCC group than in the high-grade OLK group. PD-1 was significantly correlated with CD3 (p < 0.05, R = 0.52), CD8 (p < 0.05, R = 0.46), and Foxp3 (p < 0.05, R = 0.46), and the low PD-1-expression group showed a better malignant-free survival than high PD-1 expression group in the OLK (p < 0.05).

CONCLUSION

The PD-1/PD-L1 may induce immune suppression in OLK and accelerate the progress of malignant transformation.

Defining Tumor Microenvironment as a Possible Target for Effective GEP-NENs Immunotherapy-A Systematic Review

Neuroendocrine neoplasms (NENs) are a heterogenous and recurrent group of malignancies originating from neuroendocrine secretory cells diffused on all parts of the human body. Gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs) account for most NENs. Considering the abundance of possible origins, locations, and tumor specifications, there is still no consensus about optimal treatment options for these neoplasms. In light of the escalating immunotherapeutic approaches, it is crucial to define indications for such therapy in GEP-NETs. Bearing in mind the significance of pathophysiological mechanisms and tumor microenvironment (TME) impact on carcinogenesis, defining TME structure and correlation with the immune system in GEP-NETs appears essential. This paper aimed to assess the characterization of the tumor immune microenvironment for a better understanding of the possible therapeutic options in GEP-NETS. The authors performed a systematic review, extracting papers from the PubMed, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Among 3800 articles identified through database searching, 292 were assessed for eligibility. Ultimately, 28 articles were included in the qualitative synthesis. This paper sums up the research on the immune cell infiltrates, immune checkpoint expression, cytokine profile, neoangiogenesis, and microbiome in the TME of GEP-NETs.

Tumour immune microenvironment in resected thymic carcinomas as a predictor of clinical outcome

BACKGROUND

The spatial distribution of tumour-infiltrating lymphocytes (TILs) is a novel descriptor characterising the tumour immune microenvironment (TIME). The aim of our study was to assess whether a specific TIME of surgically resected thymic carcinoma (TC) can predict tumour invasiveness, recurrence or survival.

METHODS

Digital microscopy was performed on 39 TCs immunohistochemically stained to investigate the activation of the immune checkpoint pathway (PD-L1/PD-1), along with density and spatial distribution of TILs phenotypes (CD3+, CD4+, CD8+, FOXP3+, CD56+). The impact of PD-L1 and TIL density considering the intratumoural (iTILs) and stromal (sTILs) distribution on pathological characteristics and clinical outcomes were analysed.

RESULTS

In early TC stages, we observed a higher total density of CD3+ (p = 0.05) and CD8+ (p = 0.02) TILs. PD-L1 was expressed in 71.8% of TCs. In advanced TC stages, we observed a lower density of CD3+ (p = 0.04) and CD8+ (p = 0.01) iTILs compared to early stages. Serum concentrations of PD-L1 were significantly higher in TCs compared to healthy controls: 134.43 ± 18.51 vs. 82.01 ± 6.34 pg/ml (p = 0.001), respectively. High densities of stromal CD4+ TILs (54 vs. 32%, p = 0.043) and CD8+ TILs (65 vs. 17%, p = 0.048) were associated with improved freedom from recurrence (FFR) and cause-specific survival (CSS). High density of FoxP3+ TILs were associated with improved FFR (p = 0.03) and CSS (p = 0.003).

DISCUSSION

Mapping TIL subpopulations complement the armamentarium for prognostication of TC outcomes. The improved outcome in patients with high density of TILs supports the use of immune checkpoint inhibitors in TC patients.

Monocarboxylate Transporters 1 and 4 and Prognosis in Small Bowel Neuroendocrine Tumors

Monocarboxylate transporters (MCTs) are cell membrane proteins transporting lactate, pyruvate, and ketone bodies across the plasma membrane. The prognostic role of MCTs in neuroendocrine tumors is unknown. We aimed to analyze MCT1 and MCT4 expression in small bowel neuroendocrine tumors (SB-NETs). The cohort included 109 SB-NETs and 61 SB-NET lymph node metastases from two Finnish hospitals. Tumor samples were immunohistochemically stained with MCT1 and MCT4 monoclonal antibodies. The staining intensity, percentage of positive cells, and stromal staining were assessed. MCT1 and MCT4 scores (0, 1 or 2) were composed based on the staining intensity and the percentage of positive cells. Survival analyses were performed with the Kaplan–Meier method and Cox regression, adjusted for confounders. The primary outcome was disease-specific survival (DSS). A high MCT4 intensity in SB-NETs was associated with better DSS when compared to low intensity (85.7 vs. 56.6%, p = 0.020). A high MCT4 percentage of positive cells resulted in better DSS when compared to a low percentage (77.4 vs. 49.1%, p = 0.059). MCT4 scores 0, 1, and 2 showed DSS of 52.8 vs. 58.8 vs. 100% (p = 0.025), respectively. After adjusting for confounders, the mortality hazard was lowest in the patients with a high MCT4 score. MCT1 showed no association with survival. According to our study, a high MCT4 expression is associated with an improved prognosis in SB-NETs.