To confirm that genes with promoters that are differentially methylated between HPV+ and HPV- cell lines are also differentially expressed, we carried out qPCR for CDH8 and PCDH10. We found that CDH8 and PCDH10 were significantly overexpressed in our panel of three HPV- HNSCC cell lines relative to three HPV+ cell lines, correlating with hypermethylation in the latter (see Additional File 1, Figure S11). Here, CDH8 is linked to head and neck squamous cell carcinoma.