title: Approach to early-onset colorectal cancer: clinicopathological, familial, molecular and immunohistochemical characteristics.
abstract: OBJECTIVE
  To characterize clinicopathological and familial features of early-onset colorectal cancer (CRC) and compare features of tumors with and without microsatellite instability (MSI).
  
  
  METHODS
  Forty-five patients with CRC aged 45 or younger were included in the study. Clinical information, a three-generation family history, and tumor samples were obtained. MSI status was analyzed and mismatch repair genes were examined in the MSI families. Tumors were included in a tissue microarray and an immunohistochemical study was carried out with a panel of selected antibodies.
  
  
  RESULTS
  Early onset CRC is characterized by advanced stage at diagnosis, right colon location, low-grade of differentiation, mucin production, and presence of polyps. Hereditary forms represent at least 21% of cases. Eighty-one percent of patients who died during follow-up showed a lack of expression of cyclin E, which could be a marker of poor prognosis. beta-catenin expression was normal in a high percentage of tumors.
  
  
  CONCLUSIONS
  Early-onset CRC has an important familial component, with a high proportion of tumors showing microsatellite stable. Cyclin E might be a poor prognosis factor.
authors.affiliation: Department of Surgery, Hospital Universitario 12 de Octubre, Avda. de Córdoba s/n., Madrid, Spain. josepereag@hotmail.com
authors.forename: Jose
authors.initials: J
authors.lastname: Perea
authors.forename: Edurne
authors.initials: E
authors.lastname: Alvaro
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Rodríguez
authors.forename: Cristina
authors.initials: C
authors.lastname: Gravalos
authors.forename: Eva
authors.initials: E
authors.lastname: Sánchez-Tomé
authors.forename: Barbara
authors.initials: B
authors.lastname: Rivera
authors.forename: Francisco
authors.initials: F
authors.lastname: Colina
authors.forename: Pablo
authors.initials: P
authors.lastname: Carbonell
authors.forename: Rogelio
authors.initials: R
authors.lastname: González-Sarmiento
authors.forename: Manuel
authors.initials: M
authors.lastname: Hidalgo
authors.forename: Miguel
authors.initials: M
authors.lastname: Urioste
mesh_terms: D000328:Adult; D017668:Age of Onset; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007150:Immunohistochemistry; D053842:Microsatellite Instability; D008875:Middle Aged; D009154:Mutation