Molecular drivers of oral cavity squamous cell carcinoma in non-smoking and non-drinking patients: what do we know so far?

Microbial Changes Associated With Oral Cavity Cancer Progression

OBJECTIVE

To examine the oral microbiome in the context of oral cavity squamous cell carcinoma.

STUDY DESIGN

Basic science research.

SETTING

Academic medical center.

METHODS

Oral swabs were collected from patients presenting to the operating room for management of oral cavity squamous cell carcinoma and from age- and sex-matched control patients receiving surgery for unrelated benign conditions. 16S ribosomal RNA (rRNA) sequencing was performed on genetic material obtained from swabs. A bacterial rRNA gene library was created and sequence reads were sorted into taxonomic units.

RESULTS

Thirty-one control patients (17 males) and 35 cancer patients (21 males) were enrolled. Ages ranged from 23 to 89 (median 63) for control patients and 35 to 86 (median 66) for cancer patients. Sixty-one percent of control patients and 63% of cancer patients were smokers. 16S analyses demonstrated a significant decrease in Streptococcus genera in oral cancer patients (34.11% vs 21.74% of the population, p = .04). Increases in Fusobacterium, Peptostreptococcus, Parvimonas, and Neisseria were also found. The abundance of these bacteria correlated with tumor T-stage.

CONCLUSION

16S rRNA sequencing demonstrated changes in bacterial populations in oral cavity cancer and its progression compared to noncancer controls. We found increases in bacteria genera that correspond with tumor stage-Fusobacteria, Peptostreptococcus, Parvimonas, Neisseria, and Treponema. These data suggest that oral cancer creates an environment to facilitate foreign bacterial growth, rather than implicating a specific bacterial species in carcinogenesis. These bacteria can be employed as a potential marker for tumor progression or interrogated to better characterize the tumor microenvironment.

OSCC in Never-Smokers and Never-Drinkers Is Associated with Increased Expression of Tumor-Infiltrating Lymphocytes and Better Survival

The aim of this study was to investigate the clinical, histopathologic, and immunologic differences of oral squamous cell carcinoma of never-smokers/never-drinkers and smokers/drinkers. Immunohistochemical staining for CD4, CD8, FoxP3, CD1a, and p16 was performed in 131 oral squamous cell carcinomas from smokers/drinkers and never-smokers/never-drinkers. Associations of smoking/drinking status with clinicopathologic data, immunohistochemical antibody expression, and survival were examined. Oral squamous cell carcinoma in never-smokers/never-drinkers was associated with the female gender (p < 0.001). Never-smokers/never-drinkers were older at diagnosis than smokers/drinkers (p < 0.001). Never-smokers/never-drinkers had more tumors in the maxilla, mandible, and tongue (p < 0.001). Pre-existing oral potentially malignant disorders appeared to be more common in never-smokers/never-drinkers (p < 0.001). Perineural invasion was more common in smokers/drinkers (p = 0.039). Never-smoking/never-drinking was associated with better overall survival (p = 0.004) and disease-specific survival (p = 0.029). High CD4+ T cell infiltration was associated with never-smoking/never-drinking (p = 0.008). Never-smokers/never-drinkers also showed increased CD8+ T cell infiltration (p = 0.001) and increased FoxP3+ Treg infiltration (p = 0.023). Furthermore, the total group of tumor-infiltrating lymphocytes was associated with never smoking/never drinking (p = 0.005). To conclude oral squamous cell carcinoma of the never-smokers/never-drinkers appears to be a distinct type of tumor, as it appears to have unique clinical and pathologic features and a more immunogenic microenvironment.

Defining biomarkers in oral cancer according to smoking and drinking status

Introduction

Oral Squamous Cell Carcinomas (OSCC) are mostly related to tobacco consumption eventually associated to alcohol (Smoker/Drinker patients: SD), but 25-30% of the patients have no identified risk factors (Non-Smoker/Non-Drinker patients: NSND). We hypothesized that these patients have distinguishable immune profiles that could be useful for prognosis.

Materials and Methods

Cells present in immune tumor microenvironment (TME) and blood from 87 OSCC HPV-negative patients were analyzed using a multiparameter flow cytometry assay, in a prospective case-control study. Cytokine levels in tumor supernatants and blood were determined by a cytometric bead array (CBA) assay.

Results

Normal gingiva and blood from healthy donors (HD) were used as controls. A significant increase of granulocytes (p<0.05 for blood), of monocytes-macrophages (p<0.01 for blood) and of CD4⁺ T cells expressing CD45RO and CCR6 (p<0.001 for blood; p<0.0001 for TME) as well as higher levels of IL-6 (p<0.01 for sera, p<0.05 for tumor supernatant) were observed in SD patients as compared to NSND OSCC patients and HD. High percentages of CD4⁺ T cells expressing CD45RO and CCR6 cells in tumor tissue (p=0.05) and blood (p=0.05) of SD OSCC patients were also associated with a poorer prognosis while a high percentage of regulatory T cells (Treg) in tumor tissue was associated with a more favorable prognostic factor (p=0.05). Also, a higher percentage of blood CD8⁺ T lymphocytes among CD45⁺ cells in NSND patients was associated with a better disease-free survival (p=0.004).

Conclusion

Granulocytes, monocytes-macrophages, and CD4⁺ T cells expressing CD45RO and CCR6 in blood and TME as well as serum IL-6 can therefore distinguish OSCC SD and NSND patients. Quantifying the proportion of CD4⁺ T cells expressing CD45RO and CCR6 and of Treg in SD patients and CD8⁺ T cells in NSND patients could help defining the prognostic of OSCC patients.

Epidemiological, Clinical, and Oncological Outcomes of non-Alcohol Drinking and non-Smoking Laryngeal Squamous Cell Carcinoma Patients: A Distinct Entity

Purpose: To explore the discrepancy in clinicopathological and prognostic features between smoking and alcohol drinking (SA) and non-smoking and non-alcohol drinking (NSNA) patients with laryngeal squamous cell carcinoma (LSCC). Methods: This retrospective study including 1735 patients with LSCC was conducted from January 2005 to December 2010, which were categorized into 4 groups, NSNA group, smoking only group, alcohol-drinking only group, and SA group. We compared overall survival (OS) and disease-free survival (DFS) using the Kaplan-Meier method and indicated clinicopathological features by Cox proportional hazards regression models before and after propensity score matching (PSM). Results: A total of 415 patients (23.92%) were identified as NSNA. The SA group was predominantly patients ≤60 years old (46.63%) while the NSNA group was more older (58.07%). NSNA group was more likely to present at earlier disease stage and more female. No significant difference in OS (P = .685) and DFS (P = .976) was found between the 2 groups. In addition to age and recurrence and metastasis being common independent prognostic factors in terms of OS in both groups of patients, NSNA group also exhibited other factors, namely tumor area >3.7 cm² and positive resection margin. For DFS, N + stage, tumor size >3.7 cm², and positive resection margin were prognostic features specific to NSNA group. Conclusion: The outcome is similar in LSCC patients with and without SA. NSNA group shows a distinct profile from that found in SA group. Clinicopathological features from NSNA group should be considered for LSCC management.