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Updated: Nov 23, 2025
Genome-Wide Analysis of DNA Methylation in Gastrointestinal Cancer
Published on: September 18, 2020
Microsatellite Status Affects Tumor Response and Survival in Patients Undergoing Neoadjuvant Chemotherapy for
Zhenghao Cai1,2, Weiwei Rui3, Shuchun Li1,2
1Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Background:
We assessed the association between microsatellite instability-high (MSI-H) and tumor response to neoadjuvant chemotherapy (NAC) as well as its prognostic relevance in patients with clinical stage III gastric cancer (cStage III GC).
Materials And Methods:
The NAC + surgery and the control cohorts consisted of 177 and 513 cStage III GC patients, respectively. The clinical and pathological features were compared between patients with MSI-H [n=57 (8.3%)] and microsatellite stability or microsatellite instability-low (MSS/MSI-L) [n=633 (91.7%)]. Radiological and histological response to NAC were evaluated based on response evaluation criteria in solid tumors (RECIST) and tumor regression grade (TRG) systems, respectively. The log-rank test and Cox analysis were used to determine the survival associated with MSI status as well as tumor regression between the two groups in both NAC + surgery and the control cohorts.
Results:
A statistically significant association was found between MSI-H and poor histological response to NAC (p=0.038). Significant survival priority of responders over poor-responders could only be observed in MSS/MSI-L but not in MSI-H tumors. However, patients with MSI-H had statistically significantly better survival compared to patients with MSS/MSI-L in both the NAC + surgery (hazard ratio=0.125, 95% CI, 0.017-0.897, p=0.037 ) and the control cohort (hazard ratio=0.479, 95% CI, 0.268-0.856, p=0.013).
Conclusion:
MSI-H was associated with poorer regression and better survival after NAC for cStage III GC. TRG evaluation had prognostic significance in MSS/MSI-L but not in MSI-H. Further studies are needed to assess the value of NAC for cStage III GC patients with MSI-H phenotype.
