NOS3 and atherosclerosis: Furthermore, epigenetic changes were also identified in several genes including RELA (RELA Proto-Oncogene, NF-KB Subunit), NOS3 (Nitric Oxide Synthase 3), KLF4 (KLF Transcription Factor 4) and APOE (Apolipoprotein E) that have been linked to progression of atherosclerosis [165].