title: Trop2: from development to disease.
abstract: BACKGROUND
  Trop2 was first discovered as a biomarker of invasive trophoblast cells. Since then most research has focused on its role in tumourigenesis because it is highly expressed in the vast majority of human tumours and animal models of cancer. It is also highly expressed in stem cells and in many organs during development.
  
  
  RESULTS
  We review the multifaceted role of Trop2 during development and tumourigenesis, including its role in regulating cell proliferation and migration, self-renewal, and maintenance of basement membrane integrity. We discuss the evolution of Trop2 and its related protein Epcam (Trop1), including their distinct roles. Mutation of Trop2 leads to gelatinous drop-like corneal dystrophy, whereas over-expression of Trop2 in human tumours promotes tumour aggressiveness and increases mortality. Although Trop2 expression is sufficient to promote tumour growth, the surprising discovery that Trop2-null mice have an increased risk of tumour development has highlighted the complexity of Trop2 signaling. Recently, studies have begun to identify the mechanisms underlying TROP2’s functions, including regulated intramembrane proteolysis or specific interactions with integrin b1 and claudin proteins.
  
  
  CONCLUSIONS
  Understanding the mechanisms underlying TROP2 signaling will clarify its role during development, aid in the development of better cancer treatments and unlock a promising new direction in regenerative medicine.
authors.forename: Annie R A
authors.initials: AR
authors.lastname: McDougall
authors.forename: Mary
authors.initials: M
authors.lastname: Tolcos
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Hooper
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Cole
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Wallace
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D017630:Connexins / Q000235:genetics / Q000378:metabolism; D003317:Corneal Dystrophies, Hereditary / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics*; D000097002:Gap Junction beta-1 Protein
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D017630:Connexins; D009363:Neoplasm Proteins; D000097002:Gap Junction beta-1 Protein; C499380:TACSTD2 protein, human; C544766:TROP2 protein, mouse