Methylation of HPV 16 and EPB41L3 in oral gargles: Associations with oropharyngeal cancer detection and tumor characteristics.

Oropharyngeal cancer (OPC) incidence is increasing significantly among men and often requires intensive therapy causing significant morbidity. Early detection of OPC is needed, when monotherapy can be safely delivered with less treatment-associated morbidity, while maintaining high cure rates. We conducted a study of 101 pretreatment male OPC cases matched 1:1 to 101 disease-free controls for age and smoking history. Oral gargles were collected from cases and controls with additional biopsies or aspirates from cases. The HPV SPF10 -LiPA25 PCR assay was utilized for HPV genotyping. Methylation of three CpG sites (438, 427 and 425) in the EPB41L3 gene and methylation status of the L1 (6,367, 6,389), L2 (4,257, 4,262, 4,266, 4,269, 4,275, 4,282) and E2 (3,412, 3,415, 3,417, 3,433, 3,436) CpG sites of HPV 16 positive specimens was assessed by pyrosequencing. Significant correlations were observed between tumor and oral specimens for all methylation biomarkers (p < 0.01). EPB41L3 and HPV 16 L1, L2 and E2 methylation were significantly (p < 0.0001) higher among cases than controls, regardless of early vs. late disease. When HPV 16 genes and EPB41L3 methylation status were combined in a logistic regression analysis, a sensitivity of 70.3% and a specificity of 90.9% were observed for the detection of OPC from an oral gargle. Our data suggest that methylation biomarkers measured in oral gargles may have utility in identifying OPC early. Future studies are needed to replicate these findings and to inform additional biomarkers that can maximize specificity and sensitivity for early OPC detection.