title: Id proteins--tumor markers or oncogenes?
abstract: The Id (Inhibitor of differentiation or Inhibitor of DNA-binding) proteins act as dominant negative inhibitors of differentiation-specific basic Helix-Loop-Helix (bHLH) transcription factors. Id proteins negatively regulate cellular differentiation and they induce proliferation by modulating different cell cycle regulators both by direct and indirect mechanisms. Ectopic expression of Id proteins in tissue culture models can result in cellular immortalization and abrogation of differentiation processes. Recent reports show that Id proteins are overexpressed in various cancer types implying a role of these regulatory proteins in carcinogenesis. This review focuses on the biology of the Id proteins and their role as potential oncogenes.
authors.affiliation: Department of Pathology, Harvard Center for Cancer Biology, Harvard Medical School, 200 Longwood Avenue, Building D2, Room 544A, Boston, Massachusetts 02115-5701, USA.
authors.forename: Jens
authors.initials: J
authors.lastname: Hasskarl
authors.forename: Karl
authors.initials: K
authors.lastname: Münger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D051798:Inhibitor of Differentiation Protein 1; D008969:Molecular Sequence Data; D009857:Oncogenes; D012097:Repressor Proteins; D014157:Transcription Factors / Q000032:analysis / Q000737:chemistry / Q000502:physiology*
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C497453:ID1 protein, human; D051798:Inhibitor of Differentiation Protein 1; D012097:Repressor Proteins; D014157:Transcription Factors