title: Activation of PI3K is associated with reduced survival in renal cell carcinoma.
abstract: OBJECTIVE
  The epidermal growth factor receptor- (EGFR) activated phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt) pathway is associated with tumorigenesis and progression. The aims of the present study were to determine the expression patterns of Akt pathway parameters PI3K, phosphatase and tensin homolog (PTEN), phosphor-Akt (p-Akt) and their combination, for their possible prognostic value in renal cell carcinoma (RCC). PTEN dephosphorylates the liquid product of PI3K.
  
  
  METHODS
  Tumor samples from 176 RCC patients were investigated for PTEN, p-Akt and PI3K expression by immunohistochemistry. Expression levels were correlated to clinical variables and postoperative outcome by uni- and multivariate statistical analysis.
  
  
  RESULTS
  The various expression levels within the tumor samples were independent of histological grade and tumor stage, due to different levels of activation of the PI3K/p-Akt pathway. The activation of PI3K protein was found to be significantly associated with reduced survival times (p = 0.0304, multivariate analysis). Analysis of combined biomarker expressions showed that decreased long-term survival was correlated with PTEN low/p-Akt high expression (p < 0.05).
  
  
  CONCLUSIONS
  Activation of the PI3K pathway is significantly associated with adverse clinical outcome in RCC. Analysis of biomarker combinations might identify high-risk patients and a subsequent need to adapt treatment modalities. Molecular pathways regulating PI3K activation appear to be promising targets for drug development in the clinical management of RCC patients.
authors.affiliation: Department of Urology, Eberhard Karls University Tübingen, Tübingen, Germany.
authors.forename: Axel S
authors.initials: AS
authors.lastname: Merseburger
authors.forename: Joerg
authors.initials: J
authors.lastname: Hennenlotter
authors.forename: Ursula
authors.initials: U
authors.lastname: Kuehs
authors.forename: Perikles
authors.initials: P
authors.lastname: Simon
authors.forename: Stephan
authors.initials: S
authors.lastname: Kruck
authors.forename: Eva
authors.initials: E
authors.lastname: Koch
authors.forename: Arnulf
authors.initials: A
authors.lastname: Stenzl
authors.forename: Markus A
authors.initials: MA
authors.lastname: Kuczyk
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics; D001707:Biopsy, Needle; D002292:Carcinoma, Renal Cell / Q000235:genetics* / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D009392:Nephrectomy / Q000401:mortality; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D016016:Proportional Hazards Models; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D015398:Signal Transduction; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human