title: Overexpression of the EphA2 tyrosine kinase in prostate cancer.
abstract: BACKGROUND
  Molecules that are highly expressed by human prostate cancers may serve as therapeutically relevant targets or tumor markers. Tyrosine kinases are frequently overexpressed in metastatic tumor cells and this prompted us to screen for tyrosine kinases that are overexpressed in prostate cancer cells.
  
  
  METHODS
  Expression levels of the EphA2 receptor tyrosine kinase were determined by Western blot analysis in canine and human prostate cancer cell lines and in immortalized and transformed variants of 267B1 prostatic epithelial cells. EphA2 levels in benign human prostate and prostate cancers were also determined in formalin-fixed, paraffin-embedded tissues using immunohistochemical staining.
  
  
  RESULTS
  Metastatic prostate cancer cells overexpressed EphA2 by 10-100 fold as compared with non-invasive prostatic epithelial cells. EphA2 immunoreactivity in vivo was also significantly greater in human prostate cancers as compared with benign prostate epithelium.
  
  
  CONCLUSIONS
  The EphA2 receptor tyrosine kinase is differentially expressed in human and canine prostate cancer cell lines and overexpressed in human prostate cancers as compared with benign prostate tissues. Metastasis-derived canine prostate carcinoma cell lines overexpress EphA2 and may provide pre-clinical models to further evaluate the role of EphA2 in prostate carcinogenesis. Further investigations are needed to determine the utility of EphA2 as a tumor marker and a novel target in human prostate cancer.
authors.affiliation: Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana 47907-1246, USA.
authors.forename: J
authors.initials: J
authors.lastname: Walker-Daniels
authors.forename: K
authors.initials: K
authors.lastname: Coffman
authors.forename: M
authors.initials: M
authors.lastname: Azimi
authors.forename: J S
authors.initials: JS
authors.lastname: Rhim
authors.forename: D G
authors.initials: DG
authors.lastname: Bostwick
authors.forename: P
authors.initials: P
authors.lastname: Snyder
authors.forename: B J
authors.initials: BJ
authors.lastname: Kerns
authors.forename: D J
authors.initials: DJ
authors.lastname: Waters
authors.forename: M S
authors.initials: MS
authors.lastname: Kinch
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002277:Carcinoma / Q000201:enzymology*; D004285:Dogs; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011470:Prostatic Hyperplasia / Q000201:enzymology; D011471:Prostatic Neoplasms / Q000201:enzymology*; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis*; D036104:Receptor, EphA2; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D020794:Receptor Protein-Tyrosine Kinases; D036104:Receptor, EphA2