title: Reduced expression of p21-activated protein kinase 1 correlates with poor histological differentiation in pancreatic cancer.
abstract: BACKGROUND
  P21-activated protein kinase 1 (PAK1), a main downstream effector of small Rho GTPases, is overexpressed in many malignancies. PAK1 overexpression is associated with poor prognosis in some tumor types, including breast cancer, gastric cancer, and colorectal cancer. However, the expression and clinical relevance of PAK1 expression in human pancreatic cancer remains unknown.
  
  
  METHODS
  The present study investigated the clinical and prognostic significance of PAK1 expression in pancreatic carcinoma. We examined and scored the expression of PAK1 by immunohistochemistry in 72 primary pancreatic carcinoma samples and 20 liver metastatic samples. The relationships between PAK1 and clinicopathological parameters and prognosis in primary and metastatic pancreatic cancer were analyzed.
  
  
  RESULTS
  Among the total 92 cases, primary pancreatic cancer samples had a significantly higher rate (38/72, 52.8%) of high PAK1 expression than liver metastatic samples (5/20, 25.0%) (P=0.028). Among the 72 primary pancreatic cancer patients, high PAK1 expression was associated with younger age (P=0.038) and moderately or well differentiated tumor (P=0.007). Moreover, a positive relationship was found between high PAK1 expression and overall survival (OS) (P<0.005). Patients with high PAK1 expression had a better OS than those with low PAK1 expression. Univariate and multivariate analysis by Cox regression including PAK1 and other prognostic pathological markers demonstrated high PAK1 immunostaining as a prognostic factor for survival in pancreatic cancer patients (P<0.005).
  
  
  CONCLUSIONS
  We report for the first time that PAK1 is a novel prognostic marker for pathologically confirmed human pancreatic cancer. Reduced expression of PAK1 correlates with poor histological differentiation in pancreatic cancer.
authors.forename: Juan
authors.initials: J
authors.lastname: Han
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Shu-qiang
authors.initials: SQ
authors.lastname: Yuan
authors.forename: Ying
authors.initials: Y
authors.lastname: Guo
authors.forename: Zhao-lei
authors.initials: ZL
authors.lastname: Zeng
authors.forename: Li-ren
authors.initials: LR
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: De-sen
authors.initials: DS
authors.lastname: Wang
authors.forename: Mei-yuan
authors.initials: MY
authors.lastname: Liu
authors.forename: Han
authors.initials: H
authors.lastname: Zhao
authors.forename: Kai-yan
authors.initials: KY
authors.lastname: Liu
authors.forename: Jian-wei
authors.initials: JW
authors.lastname: Liao
authors.affiliation: Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, China. zouqingfeng123@yeah.net.
authors.forename: Qing-feng
authors.initials: QF
authors.lastname: Zou
authors.forename: Rui-hua
authors.initials: RH
authors.lastname: Xu
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D011379:Prognosis; D054462:p21-Activated Kinases / Q000235:genetics*
chemical_list: C515903:PAK1 protein, human; D054462:p21-Activated Kinases