AHRR and cancer: Here, we found that the AHRR gene was differentially hypomethylated at the CpG site corresponding to the Illumina probe cg05575921 (hg19 coordinates chr5:373,378), which also intersected with a genomic region of 589 bp in chromosome 5 identified in our DMR analysis (hg19 coordinates chr5:373299-373887); this region was concordantly hypomethylated in heavy smoker subjects in both subsets of the present study (cancer-free and cancer-diagnosed), indicating the utility of this epigenetic pattern in both subsets.