title: Pepsinogen I and II expressions in situ and their correlations with serum pesignogen levels in gastric cancer and its precancerous disease.
abstract: BACKGROUND
  Serum pepsinogen (PG) I/II ratio has been widely used as "serological biopsy" for the screening of gastric cancer (GC) and atrophic gastritis (GA). However, study concerning in situ expression of PGs is currently insufficient, particularly for their relationship with serum PGs levels. This study was designed to investigate in situ expression of PGI and PGII in subjects with normal mucosa (NOR), superficial gastritis (GS), GA and GC, and to evaluate the correlations between PGs expressions in situ and in serum.
  
  
  METHODS
  185 subjects were enrolled for the study, including 30 NOR, 70 GS, 54 GA and 31 GC. PGI and PGII expressions in situ and in serum were detected by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) respectively. H. pylori immunoglobulin (Ig) G was also determined by ELISA.
  
  
  RESULTS
  In situ expressions of PGI, PGII and PGI/II ratio consistently decreased in sequence of NOR/GS- > GA- > GC. The expressions of PGI, PGII and PGI/II ratio in situ were statistically higher in youngers than in olders (P < 0.05). In the NOR subjects, PGI staining was statistically higher in males than that in females (p = 0.02). For the correlations between in situ and serum expressions of PGI, PGII and PGI/II ratio, a borderline correlation in the total study sample (r = 0.131, P = 0.076) and a statistical correlation in GA cases (r = 0.307, P = 0.027) were observed for the PGI/II ratio. The PGI expression correlated well with that of PGII in situ and in serum.
  
  
  CONCLUSIONS
  The in situ levels of PGI, PGII and PGI/II ratio sharply decreased in the GA and GC cases. The youngers exhibited higher levels of PGI, PGII and PGI/II ratios than the olders. The in situ PGI/II ratio rather than PGI and PGII alone showed certain correlation with that in serum, and the PGI expression correlated well with PGII expression. Further studies with large-scale samples are still required to validate our findings.
authors.affiliation: Tumor Etiology and Screening Department of Cancer Institute and General Surgery, Liaoning Provincial Education Department, The First Affiliated Hospital of China Medical University, Key Laboratory of Cancer Etiology and Prevention(China Medical University), 155# North Nanjing Street, Heping District, Shenyang City 110001, Liaoning Province, China. yyuan@mail.cmu.edu.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Caiyun
authors.initials: C
authors.lastname: He
authors.forename: Liping
authors.initials: L
authors.lastname: Sun
authors.forename: Nannan
authors.initials: N
authors.lastname: Dong
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan