NEIL1 and cancer: Although further experiments, such as 5-aza-dC treatment and a NEIL1 protein expression analysis for each of the latter 4 cancer types, are needed to determine the epigenetic silencing of the NEIL1 gene via promoter hypermethylation in these cancer types, we suspect that the epigenetic silencing of the NEIL1 gene via promoter hypermethylation might be the chief mechanism underlying the downregulation of NEIL1 expression in diverse human cancers.