title: Overexpression of cystatin SN positively affects survival of patients with surgically resected esophageal squamous cell carcinoma.
abstract: BACKGROUND
  Cystatin SN is a secreted protein and a cysteine proteinase inhibitor. It has been considered to be a tumor marker for gastrointestinal tract cancer in several functional researches. However, the clinicopathological and prognostic significance of Cystatin SN expression in esophageal squamous cell carcinoma (ESCC) has not been elucidated.
  
  
  METHODS
  In our study, the expression of Cystatin SN was detected in 209 surgically resected ESCC tissues and 170 peritumoral normal esophageal mucosae by immunohistochemistry. The prognostic significance of Cystatin SN expression was analysed with Kaplan-Meier plots and the Cox proportional hazards regression models.
  
  
  RESULTS
  The results showed that the immunostaining of Cystatin SN in ESCC tissues was less intense than that in the normal control tissue (P < 0.001). Compared with patients with low tumoral Cystatin SN expression, ESCC patients with tumors high-expression Cystatin SN exhibited increased disease-free survival (DFS) and overall survival (OS) (P < 0.001 and P < 0.001, respectively). Furthermore, the expression level of Cystatin SN could further stratify the ESCC patients by survival (DFS and OS) in the stage II subgroup (P < 0.001 and P < 0.001, respectively). Multivariate analyses showed that Cystatin SN expression, N status and differentiation were independent and significant predictors of survival.
  
  
  CONCLUSIONS
  We concluded that ESCC patients whose tumors express high levels of Cystatin SN have favourable survival compared with those patients with low Cystatin SN expression. Tumoral Cystatin SN expression may be an independent predictor of survival for patients with resectable ESCCs.
authors.affiliation: State Key Laboratory of Oncology in South China, Cancer Center, Sun Yet-Sen University, Guangzhou, China.
authors.forename: You-Fang
authors.initials: YF
authors.lastname: Chen
authors.forename: Gang
authors.initials: G
authors.lastname: Ma
authors.forename: Xun
authors.initials: X
authors.lastname: Cao
authors.forename: Rong-Zhen
authors.initials: RZ
authors.lastname: Luo
authors.forename: Li-Ru
authors.initials: LR
authors.lastname: He
authors.forename: Jie-Hua
authors.initials: JH
authors.lastname: He
authors.forename: Zhi-Liang
authors.initials: ZL
authors.lastname: Huang
authors.forename: Mu-Sheng
authors.initials: MS
authors.lastname: Zeng
authors.forename: Zhe-Sheng
authors.initials: ZS
authors.lastname: Wen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000401:mortality*; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism*; D004938:Esophageal Neoplasms / Q000378:metabolism / Q000401:mortality*; D000077277:Esophageal Squamous Cell Carcinoma; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D055333:Salivary Cystatins / Q000378:metabolism*; D015996:Survival Rate
chemical_list: D015853:Cysteine Proteinase Inhibitors; D055333:Salivary Cystatins