title: Organic anion transporting polypeptide 1B3 (OATP1B3) is overexpressed in colorectal tumors and is a predictor of clinical outcome.
abstract: OBJECTIVE
  OATP1B3 is an organic anion transporting polypeptide (OATP) that functions as a multispecific transporter in the normal liver. We examined the expression and clinical significance of OATP1B3 in colon cancers in tissue microarrays.
  
  
  METHODS
  Immunohistochemistry was used to assess OATP1B3 protein expression in paraffinized colon tumor tissue microarrays. OATP1B3 immunostaining was evaluated by location and intensity. Relationships between OATP1B3 expression, known prognostic variables and clinical outcomes were examined.
  
  
  RESULTS
  278 colon tumor samples of all stages were evaluated for OATP1B3 expression. OATP1B3 immunostaining was detectable in the majority (56%) of the tumor samples. Higher OATP1B3 expression was seen in lower stage tumors (p = 0.003) and lower grade (p = 0.004) tumors, but was not predictive of 5-year survival or tumor recurrence as an independent variable. Within individual tumor grades, OATP1B3 expression was associated with improved 5-year survival, but not recurrence in patients with poorly differentiated tumors.
  
  
  CONCLUSIONS
  OATP1B3 expression was seen in the majority of colon tumors and may be a marker of lower grade and lower stage tumors and may predict for improved outcome in certain tumors.
authors.affiliation: Vanderbilt University Medical Center, Nashville, TN, USA;
authors.forename: Albert Craig
authors.initials: AC
authors.lastname: Lockhart
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Harris
authors.forename: Bonnie J
authors.initials: BJ
authors.lastname: Lafleur
authors.forename: Nipun B
authors.initials: NB
authors.lastname: Merchant
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Washington
authors.forename: Murray B
authors.initials: MB
authors.lastname: Resnick
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Yeatman
authors.forename: Wooin
authors.initials: W
authors.lastname: Lee