title: Clinicopathologic Implications of PIWIL2 Expression in Colorectal Cancer.
abstract: BACKGROUND
  There are no established reports about the expression of the Piwil gene, a subfamily of the Piwi gene involved in RNA silencing and self-renewal, in colorectal carcinomas. It is known that the degree of PIWIL2 expression is higher in colorectal carcinomas. But its clinicopathologic significance remains undetermined. This study reassessed the relationship between PIWIL2 expression and the clinicopathologic parameters in colorectal carcinomas.
  
  
  METHODS
  An immunohistochemistry of PIWIL2 expression was done in 60 cases of colorectal carcinoma. This was followed by an analysis of the correlation between PIWIL2 expression and clinicopathologic features and a survival analysis.
  
  
  RESULTS
  There were 44 cases (73.3%) where the degree of PIWIL2 expression was relatively higher. The high degree of PIWIL2 expression was significantly correlated with the lower degree of differentiation (p=0.039), deep invasion (p=0.019) and perineural invasion (p=0.027). The overall survival was longer in patients with the lower degree of PIWIL2 expression than in those with the higher degree of PIWIL2 expression.
  
  
  CONCLUSIONS
  Our results showed that the degree of PIWIL2 expression was relatively higher in colorectal carcinomas and it was significantly correlated with variable clinicopathologic indicators for a poor prognosis. This indicates that PIWIL2-positive cells contribute to the progression of colorectal cancer.
authors.affiliation: Department of Pathology, Kosin University Gospel Hospital, Kosin University College of Medicine, Busan, Korea.
authors.forename: Sun-Ju
authors.initials: SJ
authors.lastname: Oh
authors.forename: Su-Mi
authors.initials: SM
authors.lastname: Kim
authors.forename: Young-Ok
authors.initials: YO
authors.lastname: Kim
authors.forename: Hee-Kyung
authors.initials: HK
authors.lastname: Chang
keywords: Colorectal cancer; PIWIL2; Piwi gene