In contrast, certain tumor-suppression genes and proteins (e.g., Kruppel-like factor 6 (KLF6), activating transcription factor 3 (ATF3), and cyclin-dependent kinase inhibitor protein (p21)) are subdued through abnormal epigenetic pathways, including histone modifications, promoter DNA methylation, and miRNA-mediated post-transcriptional alterations [138]. The gene discussed is ATF3; the disease is neoplasm.