Etiologic considerations for head and neck squamous cancers

Impact of marginalization on tobacco use in individuals diagnosed with head and neck Cancer

Background

Considerable evidence now indicates that individuals living in underprivileged neighbourhoods have higher rates of mortality and morbidity independent of individual-level characteristics. This study explored the impact of geographical marginalization on smoking cessation in a population of individuals with a diagnosis of head and neck cancer. The aims of this study were twofold: (1) assess the prevalence of smoking cessation in those with a previous diagnosis of head and neck cancer, (2) analyze the determinants of smoking alongside area-based measures of socioeconomic status.

Methods

This was a cross-sectional study. We administered a self-reported nicotine dependence package to participants between the ages of 20–90 with a previous mucosal head and neck cancer diagnosis and with a history of tobacco use. Using the Canadian Marginalization (CAN-Marg) Index tool based on 2006 Canada Census data we compared the degree of marginalization to the smoking status. For those individuals who were currently smoking, nicotine dependence and readiness to quit were assessed. A summative score of marginalization was compared to smoking status of individuals.

Results

The results from this study indicate that the summative level of marginalization developed from the combined factors of residential instability, material deprivation, ethnic concentration and dependency may be important factors in smoking cessation.

Conclusions

This analysis of determinants of smoking alongside area-based measures of socioeconomic status may implicate the need for targeted population-based smoking cessation interventions.

Application of weighted gene co-expression network analysis to identify key modules and hub genes in oral squamous cell carcinoma tumorigenesis

Purpose

Oral squamous cell carcinoma (OSCC) is one of the most common malignant diseases worldwide, yet its molecular mechanisms are largely unknown. We aimed to construct gene co-expression networks to identify key modules and hub genes involved in the pathogenesis of OSCC.

Patients and methods

We used dataset GSE30784 to construct co-expression networks by weighted gene co-expression network analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed by Database for Annotation, Visualization and Integrated Discovery (DAVID). Hub genes were screened and validated by other datasets.

Results

Turquoise and brown modules were found to be the most significantly related to tumorigenesis. Functional enrichment analysis showed that the turquoise module was associated with cell–cell adhesion, extracellular matrix and collagen catabolic process. A total of 10 hub genes (MMP1, TNFRSF12A, PLAU, FSCN1, PDPN, KRT78, EVPL, GGT6, SMIM5 and CYSRT1) were identified and validated at transcriptional and translational levels. Their genetic alteration and survival analysis were also revealed.

Conclusion

We identified two modules and 10 hub genes, which were associated with the tumorigenesis of OSCC. The two modules provided references that will advance the understanding of mechanisms of tumorigenesis in OSCC. Moreover, the hub genes may serve as biomarkers and therapeutic targets for precise diagnosis and treatment of OSCC in the future.

Occupational exposures and squamous cell carcinoma of the oral cavity, pharynx, larynx, and oesophagus: a case-control study in Sweden

OBJECTIVES

This community based case-referent study was initiated to investigate aetiological factors for squamous cell carcinoma of the upper gastrointestinal tract.

METHODS

The study was based on all Swedish men aged 40-79 living in two regions of Sweden during 1988-90. Within that base, efforts were made to identify all incident cases of squamous cell carcinoma of the oral cavity, oropharynx and hypopharynx, larynx, and oesophagus. Referents were selected as a stratified (age, region) random sample of the base. The response was 90% among cases and 85% among referents. There were 545 cases and 641 referents in the final study group. The study subjects were interviewed about several lifestyle factors and a life history of occupations and work tasks. The exposure to 17 specific agents were coded by an occupational hygienist. The relative risk (RR) of cancer was calculated by logistic regression, standardising for age, geographical region, and alcohol and tobacco consumption.

RESULTS

Exposure to asbestos was associated with an increased risk of laryngeal cancer, and a dose-response relation was present. The RR was 1.8 (95% confidence interval (95% CI) 1.1 to 3.0) in the highest exposure group. More than eight years of exposure to welding fumes was associated with an increased risk of pharyngeal cancer (RR 2.3 (1.1 to 4.7)), and laryngeal cancer (RR 2.0 (1.0 to 3.7)). There were indications of a dose-response for duration of exposure. Associations were also found for high exposure to polycyclic aromatic hydrocarbons (PAHs) and oesophageal cancer, RR 1.9 (1.1 to 3.2). Exposure to wood dust was associated with a decreased risk of cancer at the studied sites.

CONCLUSIONS

Some of the present findings confirm known or suspected associations--such as asbestos and laryngeal cancer. The study indicates that welding may cause an increased risk of pharyngeal as well as laryngeal cancer. The findings corroborate an association between exposure to PAHs and oesophageal cancer.