Infection with Human Papilloma Virus (HPV) and risk of subsites within the oral cancer.

BACKGROUND: The aim of this study was to investigate the relationship between high-risk genotypes of Human Papilloma Virus (HPV) and cancer of different subsites of the oral cavity. MATERIAL AND METHODS: A pooled analysis of five studies included on the International Head and Neck Cancer Epidemiology (INHANCE) Consortium was conducted. HPV 16 and HPV 18 were considered. Adjusted odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) for HPV and each oral cavity subsites were simultaneously estimated using multinomial logistic regression models. RESULTS: The analysis included 1157 cases and 3272 controls. This study showed a slightly higher prevalence of HPV infection among oral cancer cases than controls. In particular, an increased risk of other and not otherwise specified (NOS) sites within the oral cavity, oral tongue, palate and floor of mouth cancer was observed for overall HPV16 positivity (OR = 1.66, 95 % CI: 1.01-2.72; OR = 1.97, 95 % CI: 1.36-2.85; OR = 2.48, 95 % CI: 1.50-4.11; OR = 2.71, 95 % CI: 1.06-6.95, respectively). In particular, HPV16E7 was related to cancer of floor of mouth, oral cavity NOS and palate (OR = 2.71, 95 % CI: 1.06-6.95; OR = 3.32, 95 % CI:1.53-7.19; OR = 3.34, 95 % CI:1.38-8.06). Results were inconsistent for HPV18 due to low prevalence of infection. CONCLUSION: Our study suggests that HPV16 infection may increase the risk of developing floor of mouth, gum, tongue, and palate cancers. CLINICAL RELEVANCE: Subjects with HPV infection have a higher risk of cancer from all sites of the oral cavity.

Natural vitamin C intake and the risk of head and neck cancer: A pooled analysis in the International Head and Neck Cancer Epidemiology Consortium.

Evidence of associations between single nutrients and head and neck cancer (HNC) is still more limited and less consistent than that for fruit and vegetables. However, clarification of the protective mechanisms of fruit and vegetables is important to our understanding of HNC etiology. We investigated the association between vitamin C intake from natural sources and cancer of the oral cavity/pharynx and larynx using individual-level pooled data from ten case-control studies (5,959 cases and 12,248 controls) participating in the International Head and Neck Cancer Epidemiology (INHANCE) consortium. After harmonization of study-specific exposure information via the residual method, adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using unconditional multiple logistic regression models on quintile categories of 'non-alcohol energy-adjusted' vitamin C intake. In the presence of heterogeneity of the estimated ORs among studies, we derived those estimates from generalized linear mixed models. Higher intakes of vitamin C were inversely related to oral and pharyngeal (OR = 0.54, 95% CI: 0.45-0.65, for the fifth quintile category versus the first one, p for trend<0.001) and laryngeal cancers (OR = 0.52, 95% CI: 0.40-0.68, p for trend = 0.006), although in the presence of heterogeneity among studies for both sites. Inverse associations were consistently observed for the anatomical subsites of oral and pharyngeal cancer, and across strata of age, sex, education, body mass index, tobacco, and alcohol, for both cancer sites. The inverse association of vitamin C intake from foods with HNC may reflect a protective effect on these cancers; however, we cannot rule out other explanations.