In the only whole genome microarray study comparing AAA tissue with age-matched controls, Lenk et al. found a significant upregulation of genes and pathways related to immune response and inflammation [10], including genes previously identified in AAA tissue such as MMP9, IL1 and CTSH. Based upon pathway analysis using functional annotation from the Kyoto Encyclopedia of Genes and Genomes (KEGG) [11], the most significantly upregulated set of genes was the KEGG pathway “Natural Killer (NK) Cell Mediated Cytotoxicity” (Figure 1). Here, MMP9 is linked to triple-A syndrome.