Using DNA microarray, the researchers analyzed the gene expression data previously detected from primary tumors located in the oral cavity and oropharynx for their differential expression between nonsmoking and nondrinking patients (n = 15) and smoking and drinking patients (n = 89). Student's T-test (P < .05) and 10-fold cross-validation procedure (100 times repeated) were performed to determine differentially expressed genes. The study found that nonsmoking and nondrinking patients were older, mostly female, and had oral cavity localized tumors. In contrast, smoking and drinking patients were younger male patients with 81% oral cavity and 19% oropharynx tumors. A set of 49 differentially expressed genes was detected. Amongst others, 7 genes related to Interferon-gamma were upregulated and 2 genes linked to nuclear factor kappa B pathway were downregulated.
The authors conclude that differentially expressed genes in nonsmoking and nondrinking patients possibly indicate the presence of a different cellular response to carcinogenic events in these patients. The authors state that further studies are warranted to validate this gene set and explore possible therapeutic implications to improve prognosis for these patients with head and neck squamous cell carcinoma.
(Source: Oral Diseases. June 2011, Volume 33, Issue 6, pages 817 to 823; accessed online September 29, 2011)