There were several tumor suppressor genes implicated in cancer susceptibility, including both high penetrance genes (i.e., NF1, PTEN) [43,44,45] and lower penetrance genes (PALB2, ATM) [46,47,48], that were found to have higher mean methylation values in the promoter regions of WTC exposed compared to unexposed individuals. This evidence concerns the gene PTEN and neoplasm.