title: [Influence of neoadjuvant chemotherapy on microsatellite instability in gastric carcinoma].
abstract: OBJECTIVE
  Most results from clinical trials of neoadjuvant chemotherapy for gastric carcinoma are certain. Meanwhile, microsatellite instability (MSI) is thought to be a new mechanism of cell canceration. This study was to investigate the influence of neoadjuvant chemotherapy on MSI in gastric carcinoma.
  
  
  METHODS
  Two microsatellite loci D2S123 and D3S1298 in tumor samples from 48 patients with gastric carcinoma, received preoperative chemotherapy of 5-fluorouracil (5-FU) and leucovorin (CF), were analyzed by polymerase chain reaction (PCR), electrophoresis on 8% denatured polyacrylamide gel, and silver staining. The microsatellite statuses of preoperative and postoperative specimens were compared. Chi-square test was used to analyze the influence of neoadjuvant chemotherapy on MSI in gastric carcinoma.
  
  
  RESULTS
  The detection rate of MSI was significantly higher in preoperative samples than in postoperative samples (31.3% vs. 12.5%, P=0.026). After neoadjuvant chemotherapy, 9 cases changed from MSI-positive to MSI-negative, while no MSI-negative cases became MSI-positive.
  
  
  CONCLUSIONS
  The neoadjuvant chemotherapy regimen of 5-FU/CF can induce some MSI-positive gastric carcinoma change to MSI-negative, but has no effect on MSI-negative cases.
authors.affiliation: State Key Laboratory of Oncology in South China, Guangzhou, Guangdong, 510060, P. R. China. d2s123@163.com
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Sun
authors.forename: You-Qing
authors.initials: YQ
authors.lastname: Zhan
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Jin-Tian
authors.initials: JT
authors.lastname: Li
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Chen
authors.forename: Ru-Hua
authors.initials: RH
authors.lastname: Zhang
authors.forename: Da-Zhi
authors.initials: DZ
authors.lastname: Xu
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D004273:DNA, Neoplasm / Q000235:genetics; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage; D053842:Microsatellite Instability / Q000187:drug effects*; D018895:Microsatellite Repeats / Q000235:genetics; D020360:Neoadjuvant Therapy; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery
chemical_list: D004273:DNA, Neoplasm; D002955:Leucovorin; D005472:Fluorouracil