High PD-L1 Expression on Tumor Cells Indicates Worse Overall Survival in Advanced Oral Squamous Cell Carcinomas of the Tongue and the Floor of the Mouth but Not in Other Oral Compartments

Does high PD-L1 expression reduce the risk of relapse after definitive surgery in patients with oral cavity cancer?

BACKGROUND

Uncovering the molecular mechanisms of cancer pathogenesis is crucial for improving survival outcomes.

AIMS

This study investigates the impact of programmed death ligand 1 (PD-L1) expression on the risk of progression in patients with oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

The retrospective study included adult patients diagnosed with OSCC between January 2012 and December 2023. PD-L1 expression in tissue removed by definitive surgery was evaluated using immunohistochemistry, and tumor proportion score (TPS) and combined positive score (CPS) were calculated. Survival analyses were performed to assess its prognostic implications.

RESULTS

Among the 96 patients, TPS and CPS were 20% or above in 52 (54.2%) and 65 (67.7%) cases, respectively. TPS ≥20% was associated with mucosal lip location, earlier disease stage, and decreased risk of progression. The multivariate Cox regression model revealed that stage III/IV disease (HR: 2.176, 95%CI: 1.085-4.376, p = .029) and TPS ≥20% (HR: 0.241, 95%CI: 0.066-0.879, p = .031) were independent risk factors for progression-free survival.

CONCLUSIONS

The study revealed that increased tumoral PD-L1 expression may reduce the risk of progression in patients with OSCC.

SIGNIFICANCE

These findings underscore the potential prognostic significance of PD-L1 expression in OSCC following surgical resection.

Prognostic significance of IL-33 and ST2 expression in head and neck squamous cell carcinoma: a systematic review

Background

Interleukin-33 (IL-33) and Suppression of tumorigenicity 2 (ST2) expression are strongly associated with tumor growth and progression in diverse cancers, indicating the possibility of targeting the IL-33/ST2 axis pathway as a favorable therapeutic approach. However, the specific implications of IL-33/ST2 expression in Head and Neck Squamous Cell Carcinoma (HNSCC) prognosis are not fully understood. Thus, there is a need for more comprehensive research to verify the tasks and clinical significance of IL-33 and ST2 in HNSCC.

Objectives

The objective of this study was to evaluate the potential of differentially expressed IL-33 and ST2 in tumor tissues that could serve as novel biomarkers in HNSCC.

Material & methods

The Web of Science, Scopus, and PubMed electronic databases were searched and analyzed from January 2013 to July 2023.

Results

Nine studies fulfilling the inclusion criteria were analyzed. These selected studies were mainly having observational analytical study design, predominantly conducted within the Southeast Asian population. IL-33, primarily located in the stroma, demonstrates enhanced expression within carcinoma-associated fibroblasts (CAFs). Overexpression of IL-33 in CAFs correlates with its expression in tumor cells, as per some of these reports. Elevated IL-33 levels in CAFs are associated with unfavorable clinical outcomes. Increased IL-33 expression is related to poor nodal metastasis-free survival, indicating an adverse prognosis in HNSCC. In HNSCC, tumor cells and regulatory T cells (Tregs) expressed ST2. The degree of ST2 expression on Tregs corresponds to the abundance of IL-33 expressing CAFs. IL-33 increases the Tregs density and amplifies their suppressive capability. Poorer survival outcomes in HNSCC are linked to elevated ST2 expression in Tregs combined with the existence of IL-33-expressing CAFs.

Conclusion

CAF-driven cancer invasiveness relies on IL-33 signaling via paracrine and autocrine pathways. IL-33 may be a prognostic biomarker and therapeutic target, aiming to improve prognosis and survival in HNSCC. The IL-33/ST2 axis significantly configures the tumor microenvironment and tumor aggressiveness in HNSCC. The role of serum IL33 and ST2 remains to be further studied in HNSCC.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/i, identifier (CRD42023447963).

The Expression of PDL-1 and PD1 in the Microenvironment of Oral Squamous Cell Carcinoma

OBJECTIVE

Immune checkpoint proteins, especially PD-1/PD-L1, play a vital role in controlling the intensity and duration of the immune response. However, cancer cells often over-expression PDL-1 on their surfaces, which leads to the permanent activation of the PD-1/PDL-1 pathway and exhaustion of T cells and creates a resistant tumor microenvironment. This study aimed to analyze PD-1, PD-L1 expression in tumor cells (PDL-1/TC) and in Tumor-Infiltrating Lymphocytes (PDL-1/TILS) of OSCC patients and associated with and to correlate it with histologic grade of malignancy and clinicopathologic parameters.

METHODS

The sample consisted of 43 archived specimens of 43 patients of OSCC with Clinical features (gender, age, smoking, clinical stage) collected from medical records between 2014-2021. The intensity of PD-1, PDL-1/TC, PDL-1/TILS, positive cells were assessed by immunohistochemistry.

RESULT

PDL-1/TILS and PDL-1/TC were observed in all specimens except two cases in well-differentiated were negative. PDL-1/TILS was significant between histological grades(P=0.004<0.05). There was no significant between PDL-1/TC and PDL-1/TILS and between poorly differentiated and moderately differentiated groups' ROC P values (P=0.133, 0.340>0.05) respectively. There is a difference between PDL-1/TC and PDL-1/TILS between poorly differentiated and well-differentiated groups ROC P value (0.005, 0.028), Sensitivity (0.857, 0.857), specificity (0.765, 0.824) respectively and there is a difference between and PDL-1/TILS moderate differentiated and well-differentiated groups ROC P value (0.133,) Sensitivity (0.737), specificity (0.765). No differences between PDL-1/TC and moderate and well-differentiated groups P value (0.173). There is a significant correlation between PDL-1/TC and PDL-1/TILS with an age P>65 value (0.032) in the well-differentiated group. PDL-1/TC and PDL-1/TILS with the depth of invasion (DOI) in the well-differentiated group. No significant correlation was obtained between PDL-1/TC and PDL-1/TILS and smoking, clinical stage, and gender. No significant correlation was obtained between PD1 and the histological grades or clinicopathologic characteristics.

CONCLUSION

PDL-1/TILS and PDL-1/TC are independent prognostic factors in OSCC and PDL1-/TILS has an important role.

Pathological examination of factors involved in PD-L1 expression in patients with oral tongue squamous cell carcinoma

BACKGROUND

Tumor tissues comprise cancer cells and stromal cells, and their interactions form the cancer microenvironment. Therefore, treatments targeting cells other than cancer cells are also actively being developed, and among them, treatment targeting PD-1, an immune checkpoint molecule that is important in tumor immune evasion, has also been indicated for head and neck cancer. PD-L1, a ligand of PD-1, is expressed in both tumor cells and stromal cells, and the scoring system based on the combined positivity rates of both types of cells, the combined positive score (CPS), is used for predicting treatment effect. However, much is unknown regarding the expression of PD-L1. In this study, we histopathologically examined factors controlling the expression of PD-1/PD-L1. This study included 37 patients who underwent resection surgery for tongue squamous cell carcinoma in the Department of Oral and Maxillofacial Surgery at Tokyo Dental College Suidobashi Hospital. The expression levels of PD-L1, α-SMA, and p53 were assessed by immunohistochemical staining.

RESULTS

Seven participants had CPS ≥ 20, twenty-four participants had 1 ≤ CPS < 20, and six participants had CPS < 1. The overall positivity rate of α-SMA, a marker for cancer-associated fibroblasts (CAFs), was 27% (10/37 participants), and the positivity rates of α-SMA for the three CPS groups were 85.7% (6/7 participants), 16.7% (4/24 participants), and 0% (0/6 participants), respectively. In addition, the overall positivity rate of p53 was 37.8% (14/37 participants), and the positivity rates of p53 for the three CPS groups were 71.4% (5/7 participants), 37.5% (9/24 participants), and 0% (0/6 participants), respectively.

CONCLUSIONS

The expression of PD-L1 demonstrated an association with α-SMA and p53 positivity. In addition, compared with the expression of p53, the expression of α-SMA demonstrated a higher association with PD-L1 expression in patients with a high CPS. The abovementioned findings suggest that the interactions between CAFs, cancer cells, and immunocompetent cells may regulate the expression of PD-L1.

Interaction of microbiota, mucosal malignancies, and immunotherapy-Mechanistic insights

The microbiome has emerged as a crucial modulator of host-immune interactions and clearly impacts tumor development and therapy efficacy. The microbiome is a double-edged sword in cancer development and therapy as both pro-tumorigenic and anti-tumorigenic bacterial taxa have been identified. The staggering number of association-based studies in various tumor types has led to an enormous amount of data that makes it difficult to identify bacteria that promote tumor development or modulate therapy efficacy from bystander bacteria. Here we aim to comprehensively summarize the current knowledge of microbiome-host immunity interactions and cancer therapy in various mucosal tissues to find commonalities and thus identify potential functionally relevant bacterial taxa. Moreover, we also review recent studies identifying specific bacteria and mechanisms through which the microbiome modulates cancer development and therapy efficacy.

High PD-L1 expression on immune cells along with increased density of tumor-infiltrating lymphocytes predicts a favorable survival outcome for patients with loco-regionally advanced head and neck cancer: early results from a prospective study

Introduction

In the era of personalized medicine and treatment optimization, use of immune biomarkers holds promise for estimating the prognosis of patients with head and neck squamous cell carcinoma (HNSCC) undergoing definitive treatment.

Methods

To evaluate the prognostic potential of immune biomarkers, we conducted a prospective monocentric cohort study with loco-regionally advanced HNSCC patients indicated for definitive radiotherapy/radiochemotherapy at the Department of Oncology, Ostrava University Hospital, Czech Republic, between June 2020 and August 2023. We focused on the expression of programmed death ligand 1 (PD-L1) and tumor-infiltrating lymphocytes (TILs) relative to overall survival (OS) and specific survival rates. Associations between biomarkers and survival rates were assessed by crude and adjusted hazard ratios (cHR, aHR, respectively) obtained from Cox proportional hazards regression.

Results

Among a total of 55 patients within a median follow-up of 19.7 months, there were 21 (38.2%) all-cause deaths and 15 (27.3%) cancer-related deaths. An overall survival (OS) rate of 61.8% and a disease-specific survival (DSS) rate of 72.7% were recorded. A significant association between survival rates and a ≥10% difference in PD-L1 expression on immune versus tumor cells (high PD-L1IC expression) was documented regardless of the type of analysis (univariate or multivariate). In addition, a stronger association was confirmed for OS and the composite biomarker high PD-L1IC expression along with either median-higher CD8+ TIL count or increased TIL density ≥30%, as indicated by an aHR of 0.08 (95% CI, 0.01 to 0.52) and 0.07 (95% CI, 0.01 to 0.46), respectively. Similar results were demonstrated for other specific survival rates.

Discussion

The early outcomes of the present study suggest the utility of a strong prognostic factor involving a composite biomarker high PD-L1IC expression along with increased TIL density in HNSCC patients undergoing definitive radiotherapy and radiochemotherapy.

Trial registration

The study is registered with Clinicaltrials.gov. - NCT05941676.

The role of p21-activated kinase 4 in the progression of oral squamous cell carcinoma by targeting PI3K-AKT signaling pathway

BACKGROUND

Oral squamous carcinoma (OSCC), the most common head and neck malignancy, has a strong propensity for malignant proliferation and metastasis, which will decrease the survival of patients. P21-activated kinase 4 (PAK4), a classical serine/threonine protein kinase with multiple cellular functions, has an essential role in cancer cell migration and invasion. Here, we elucidated the function and possible molecular mechanisms of the effect of PAK4 on the biological behaviors of OSCC.

METHODS

The expression of genes and protein was detected by real-time PCR and western blotting. We used oral squamous carcinoma cell lines, Tca8117, Cal 27, SCC 4, and SCC 9 for validation of our cell function data. Flow cytometry, 3D cultures, and clone formation assay were used to detect proliferation of cells. RNA sequencing and bioinformatic analysis was performed to determine the potential function of PAK4.

RESULTS

Immunohistochemistry, western blotting and real-time PCR demonstrated that PAK4 expression was up-regulated in OSCC tissues. Overexpression of PAK4 promoted the proliferation, migration and invasion of OSCC cell lines. RNA sequencing (RNA-seq) for the transcriptome-wide analysis of differential gene expression followed by bioinformatic analysis was performed to determine the potential function of PAK4. Based on the KEGG enrichment analysis and GO analysis of differential expression genes (DEGs) we found that PAK4 promotes the cell-cycle machinery, which associated with 44 regulated genes, thereby promoting cancer cell differentiation.

CONCLUSIONS

This study demonstrates that the PAK4 regulates the biological behaviors of OSCC by PI3K-AKT signaling pathway, and these findings might provide a novel strategy for OSCC treatment.

VISTA H-Score Is Significantly Associated with a 5-Year DFS Rate in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer in the world. Despite its prevalence, it is often recognized in advanced stages (III or IV) when it has already spread to local lymph nodes. In this study, we investigate the V-domain Ig suppressor of T cell activation (VISTA) as a potential prognostic factor in OSCC. Tissue samples were collected from 71 oral squamous cell carcinoma patients to determine protein expression levels (using immunochemistry and the semi-quantitative H-score method). Moreover, RT-qPCR was additionally performed in 35 patients. Clinical factors in our cohort study had no impact on VISTA expression. However, VISTA expression is largely correlated with Il-33 levels in tumor cells and lymphocytes and with PD-L1 in tumor cells. The impact of VISTA expression on overall survival (OS) is rather limited, but in the case of a 5-year survival rate, a significant association has been proven. VISTA seems to be a rather weak clinicopathological marker but needs further evaluation in the context of survival. In addition, the potential of VISTA combination with Il-33 or PD-L1 should be further investigated in OSCC.

Epithelial PD-L1 expression at tumor front predicts overall survival in a cohort of oral squamous cell carcinomas from Sudan

BACKGROUND

We recently described the tumor immune microenvironment (TIME) in oral squamous cell carcinomas (OSCC) from Sudan by assessing the core of the lesions. However, the invasive tumor front (ITF) is the most active part of OSCC lesions; thus, TIME should also be characterized at the ITF in this patient cohort.

OBJECTIVES

We aimed to evaluate patterns of immune cell infiltration at the ITF in a cohort of OSCC patients from Sudan previously investigated at the tumor center and their association with clinicopathological parameters.

METHODS

This study was performed on a prospective cohort of 22 OSCC patients attending Khartoum Dental Teaching Hospital with a median follow-up of 48 months. Inflammatory infiltrate densities of CD4-, CD8-, FoxP3-, CD20-, CD66b-, M1 (CD80/CD68)-, M2 (CD163/CD68)-, and PD-L1-positive cells were assessed at the ITF by immunohistochemistry, followed by digital quantitative analysis at the stromal and epithelial compartments separately. Histopathological parameters such as the worst pattern of invasion, differentiation, and tumor budding (TB) were also assessed. Correlations between clinicopathological parameters and survival analysis were investigated using SPSS.

RESULTS

All inflammatory cell subsets investigated were found to be higher in the stromal compartment as compared to the epithelial one, except for the PD-L1⁺ subset. Stromal infiltration with the CD8⁺ cell subset was associated with low TB. Kaplan-Meier analyses identified higher epithelial and stromal CD4⁺ cell subsets. The presence of PD-L1 was found to be associated with unfavorable overall survival. Further, Cox's regression analysis using an age- and tumor-stage-adjusted model identified epithelial PD-L1 expression at the ITF as the only independent prognosticator.

CONCLUSIONS

Epithelial PD-L1 expression at the ITF was found to be an independent prognostic biomarker for OSCC in a cohort of Sudanese patients.

Prognostic value of PD-1, PD-L1 and PD-L2 deserves attention in head and neck cancer

Head and neck cancer has high heterogeneity with poor prognosis, and emerging researches have been focusing on the prognostic markers of head and neck cancer. PD-L1 expression is an important basis for strategies of immunosuppressive treatment, but whether it has prognostic value is still controversial. Although meta-analysis on PD-L1 expression versus head and neck cancer prognosis has been performed, the conclusions are controversial. Since PD-L1 and PD-L2 are two receptors for PD-1, here we summarize and analyze the different prognostic values of PD-1, PD-L1, and PD-L2 in head and neck cancer in the context of different cell types, tissue localization and protein forms. We propose that for head and neck cancer, the risk warning value of PD-1/PD-L1 expression in precancerous lesions is worthy of attention, and the prognostic value of PD-L1 expression at different subcellular levels as well as the judgment convenience of prognostic value of PD-1, PD-L1, PD-L2 should be fully considered. The PD-L1 evaluation systems established based on immune checkpoint inhibitors (ICIs) are not fully suitable for the evaluation of PD-L1 prognosis in head and neck cancer. It is necessary to establish a new PD-L1 evaluation system based on the prognosis for further explorations. The prognostic value of PD-L1, PD-L2 expression in head and neck cancer may be different for early-stage and late-stage samples, and further stratification is required.

PD-L1 in oral squamous cell carcinoma: A key biomarker from the laboratory to the bedside

OBJECTIVES AND BACKGROUND

Oral squamous cell carcinoma (OSCC) is a highly malignant disease with an increasing incidence. The need to improve therapeutic strategies for patients affected by OSCC is an urgent challenge. Currently, the advent of immunotherapy represents an important step toward this aim. Programmed cell death-ligand 1 (PD-L1), a membrane protein that can be expressed on tumor and inflammatory cells is a key biomarker whose expression is determined by means of immunohistochemistry and is necessary for selecting patients for immunotherapy.

METHODS

In this study, we review the methods of PD-L1 assessment and outcomes achieved with immunotherapy in the treatment of OSCC patients.

RESULTS

Based on a meta-analysis we demonstrate a lack of prognostic significance of PD-L1 in OSCC.

CONCLUSIONS

We also highlight unresolved issues including difficulties in standardizing PD-L1 evaluation and discuss future opportunities such as leveraging digital pathology.