Among the analysis of the hypermethylation status of 158 lung tumors, XPC hypermethylation is more common in nonsmokers (39 of 94, 41%) than in smokers (14 of 64, 22%; P=0.010).
Analysis of published data indicated allelic loss of XPC in most human lung tumors and allelic loss of Gadd45a in some human lung and other cancer types.