Outline of the study. We collected blood samples and isolated mononuclear cells for DNA and RNA extraction from four all male groups: AAA smokers, AAA non-smokers, control smokers and control non-smokers. Methylation data were obtained using the Illumina 450k HumanMethylation Bead Chip [26] and analyzed using the R language and multiple Bioconductor packages. Principal component analysis and linear analysis of CpG island subsets identified four regions with significant differences in methylation with respect to AAA: kelch-like family member 35 (KLHL35), calponin 2 (CNN2), serpin peptidase inhibitor clade B (ovalbumin) member 9 (SERPINB9), and adenylate cyclase 10 pseudogene 1 (ADCY10P1) (pseudogene). Follow-up studies included RT-PCR and immunostaining for CNN2 and SERPINB9. Symbols: AAA, abdominal aortic aneurysm; FFPE, formalin-fixed paraffin-embedded tissue; QC, quality control.