title: Identification and validation of Kallikrein-ralated peptidase 11 as a novel prognostic marker of gastric cancer based on immunohistochemistry.
abstract: OBJECTIVE
  It is important to identify and validate the differentially expressed genes in gastric cancer to screen diagnostic and/or prognostic tumor markers.
  
  
  METHODS
  cDNA expression microarray, gene set enrichment analysis, and bioinformatics approaches were used to screen the differentially expressed genes between gastric cancer tissues and adjacent non-cancerous mucosa. A novel candidate prognostic marker, Kallikrein-related peptidase 11 (KLK11), was validated in 400 Chinese gastric cancer patients. KLK11 expression in gastric cancer tissues was detected using real-time PCR and Western blot. KLK11 protein expression was further analyzed by immunostaining on tissue microarray, followed with clinicopathological significance and survival analysis.
  
  
  RESULTS
  KLK11 expression was significantly decreased in gastric cancer compared with that in normal gastric mucosa (P<0.001). Furthermore, KLK11 expression was much lower in poorly differentiated cancer samples than that in well-differentiated group (P<0.01). Survival analysis showed that negative KLK11 expression was associated with nearly fivefold increased risk of distant metastasis after curative gastrectomy (HR 4.65, P<0.01). Multivariate Cox regression analysis showed that KLK11 expression emerged as a significant independent prognostic factor for disease-free survival and overall survival (P<0.05).
  
  
  CONCLUSIONS
  The results indicated that KLK11 expression was decreased in gastric cancer and might serve as a novel independent prognostic marker.
authors: Department of General Surgery, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, PR China.
authors: Yu-Gang
authors: YG
authors: Wen
authors: Quan
authors: Q
authors: Wang
authors: Chong-Zhi
authors: CZ
authors: Zhou
authors: Dong-Wang
authors: DW
authors: Yan
authors: Guo-Qiang
authors: GQ
authors: Qiu
authors: Chun
authors: C
authors: Yang
authors: Hua-Mei
authors: HM
authors: Tang
authors: Zhi-Hai
authors: ZH
authors: Peng