NFE2L2 and head and neck squamous cell carcinoma: Similar to clinical findings, the expression of NRF2 protein was markedly higher in the HNSCC cell lines than in dysplasia oral keratinocytes (DOK; Figure 1E), and lower levels of NRF2 protein were observed in normal human oral keratinocytes (NHOK) compared to DOK and HNSCC cells (Figure S3).