title: Loss of p27 expression and microsatellite instability in sporadic colorectal cancer.
abstract: BACKGROUND
  The role of the loss of p27 protein expression in the oncogenesis of colorectal cancer is still in debate. In this study, we prospectively examined the immunohistochemical expression of p27 in 108 consecutive colorectal cancers, and we analysed the relationship with the results, the clinicopathological data, microsatellite instability (MSI) and other genetic alterations of tumours.
  
  
  METHODS
  Unselected patients (108) who underwent curative colorectal resection for sporadic colorectal cancer in a three-year period were evaluated for MSI using 6 microsatellite markers, and for the presence of p27, p53, Fhit, Mlh1 and Msh2 proteins by means of immunostaining. The relationships between these markers were analysed. p27 protein expression was examined for association with disease recurrences and survival.
  
  
  RESULTS
  Lack of p27 expression was noted in 33 out of 108 (30.5%) colorectal cancer cases (P<0.05). This altered expression was significantly higher in proximal cancers (P<0.05), mucinous tumours (P<0.001), poorly differentiated histology (P<0.01), cancers with MSI (P<0.05), tumours with altered expression of Mlh1 (P<0.01), of Msh2 (P<0.05), and of Fhit (P<0.01). Overall survival was better in the patient group with altered level of phenotypic p27 expression, although the difference does not reach statistical significance (P=0.069). The analysis performed only for patients with tumour at stage II showed significantly better survival when the tumour exhibited altered p27 expression (P<0.02).
  
  
  CONCLUSIONS
  The results of the present study support the hypothesis that altered expression of p27 may be part of the genetic pathway involving MSI, which is responsible for the development of some colorectal cancers.
authors.affiliation: Department of Surgical Sciences, Section of General Surgical Clinics and Surgical Therapy, Parma University, Medical School, Via Gramsci 14, 43100 Parma, Italy. leosarli@unipr.it
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Sarli
authors.forename: Lorena
authors.initials: L
authors.lastname: Bottarelli
authors.forename: Cinzia
authors.initials: C
authors.lastname: Azzoni
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Campanini
authors.forename: Gabriella
authors.initials: G
authors.lastname: Di Cola
authors.forename: Angela Luciana
authors.initials: AL
authors.lastname: Barilli
authors.forename: Federico
authors.initials: F
authors.lastname: Marchesi
authors.forename: Antonio
authors.initials: A
authors.lastname: Mazzeo
authors.forename: Carlo
authors.initials: C
authors.lastname: Salvemini
authors.forename: Silvia
authors.initials: S
authors.lastname: Morari
authors.forename: Davide
authors.initials: D
authors.lastname: Di Mauro
authors.forename: Enrico
authors.initials: E
authors.lastname: Donadei
authors.forename: Fransesca
authors.initials: F
authors.lastname: Necchi
authors.forename: Luigi
authors.initials: L
authors.lastname: Roncoroni
authors.forename: Cesare
authors.initials: C
authors.lastname: Bordi
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D019656:Loss of Heterozygosity; D008297:Male; D053842:Microsatellite Instability; D018895:Microsatellite Repeats; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis*; D016896:Treatment Outcome
chemical_list: D018809:Proliferating Cell Nuclear Antigen; C413374:p27 antigen