National Center for Biotechnology Information NCBI NLM MEDLINE genetic review gene expression regulation humans pubmed abstract nih national institutes of health national library of medicine risk factors Colitis disease progression oxidative stress pmid:24944468 pmc4051917 doi:10.3748/wjg.v20.i22.6774 marco scarpa ignazio castagliuolo imerio angriman cell transformation neoplastic* / genetics neoplastic* / immunology neoplastic* / metabolism neoplastic* / pathology ulcerative / complications* ulcerative / genetics ulcerative / immunology ulcerative / metabolism ulcerative / pathology colonic neoplasms / etiology* colonic neoplasms / genetics colonic neoplasms / immunology colonic neoplasms / metabolism colonic neoplasms / pathology dna damage dna methylation epigenesis neoplastic inflammation mediators / metabolism neoplasm grading oncogenes t-lymphocytes / immunology t-lymphocytes / metabolism