Chemosensitivity and survival in gastric cancer patients with microsatellite instability

Ann Surg Oncol. 2009 Sep;16(9):2510-5. doi: 10.1245/s10434-009-0580-8. Epub 2009 Jun 30.


Introduction: Conflicting data exist regarding the relevance of high-frequency microsatellite instability (MSI-H) for predicting the prognosis and benefits of 5-fluorouracil (5-FU)-based chemotherapy. This study investigated the usefulness of MSI as either a prognostic indicator or predictor of distinct clinical attributes regarding the use of adjuvant chemotherapy with 5-FU and its analogues in gastric cancer.

Materials and methods: Data and tumor specimens were collected from 240 gastric cancer patients from 1993 to 2002. Five microsatellite loci were analyzed using a high-intensity microsatellite analysis reported previously. A Cox proportional hazard model was used to compare the clinical data and survival as well as any associations between MSI and 5-FU treatment status of patients with MSI or microsatellite stability (MSS) gastric cancers. A 3-(4,5-dimethyl-2-thiazolyl) -2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was conducted in 168 cases to investigate chemosensitivity to 5-FU.

Results: This analysis identified 22 MSI-H (9.4%), 25 MSI-L (10.7%), and 193 MSS (79.9%) tumors. Gastric cancer with MSI-H tended to have increased likelihood to show higher age, antral location of the tumor, and lymph vessel involvement (P < 0.05). Univariate analyses failed to show any difference between the MSI-H and MSS/MSI-L groups with respect to overall survival. Furthermore, survival after the administration of 5-FU did not correlate with MSI status, and MSI was not associated with 5-FU sensitivity by MTT assay.

Conclusion: The results of this study indicate that MSI status has no clear influence on overall survival or response to 5-FU in gastric cancer.

MeSH terms

  • Aged
  • Antimetabolites, Antineoplastic / therapeutic use*
  • Disease Progression
  • Female
  • Fluorouracil / therapeutic use*
  • Humans
  • Lymphatic Metastasis
  • Male
  • Microsatellite Instability*
  • Middle Aged
  • Neoplasm Recurrence, Local / genetics*
  • Prognosis
  • Retrospective Studies
  • Stomach Neoplasms / drug therapy*
  • Stomach Neoplasms / genetics*
  • Stomach Neoplasms / mortality
  • Survival Rate


  • Antimetabolites, Antineoplastic
  • Fluorouracil