Histopathological analysis of oral squamous cell carcinoma in nonsmokers and nondrinkers

Abstract

A distinct clinical subgroup of nonsmoking (NS) and nondrinking (ND) patients with oral squamous cell carcinoma (OSCC) has been identified. The objective of the study was to assess this cohort for molecular variations in the disease process and if these could be attributed to clinical or epidemiological characteristics. One hundred and twenty-nine consecutive patients (71 males, 58 females) treated for OSCC were assessed at the Royal Melbourne Hospital between January 2007 and July 2010. Formalin-fixed paraffin embedded (FFPE) sections were stained for p53, p16, cyclin D1, and epidermal growth factor receptor (EGFR). Biomarker overexpression was observed in 72 (56%) cases for p53, 23 (18%) for p16, 45 (35%) for cyclin D1, and 72 (56%) for EGFR. Multiple logistic regression analysis revealed that tongue tumors ( p = 0.012) and late stage cancers ( p = 0.031) were more likely to have cyclin D1 overexpression. Further, older patients significantly more often had cyclin D1 overexpression ( p = 0.008) and NSND patients had more p16 expression ( p = 0.043). In contrast, smokers were more likely to have EGFR overexpression ( p = 0.033). Concurrent overexpression of p53 and cyclin D1 were observed ( p = 0.030). Smoking, site, and stage of OSCC can influence biomarker expression, with p16 overexpression specifically observed in NSND, indicating fundamental differences in the mechanisms of oral carcinogenesis among different patient cohorts.