Aims Although frameshift variants in the microsatellite area of shugoshin 1 (SGO1) have been reported in the context of microsatellite instability-high (MSI-H)/deficient mismatch repair gastrointestinal cancer, most have been evaluated only in early stage I–III patients, and only two of its five microsatellite regions have been evaluated. Therefore, we investigated the frequency and MSI status of microsatellite frameshift variants in gastric cancer cases, including stage IV.
Methods In a total of 55 cases, 30 gastric cancer resection and 25 non-resection cases, DNA was extracted from both tumour and normal parts and PCR was performed. The variant was confirmed by TA cloning, and MSI was evaluated using GeneMapper software.
Results A frameshift variant of c.973delA was observed in 16 of the 45 evaluable cases. Its frequency was 35.6%. Of the 25 cases that could be assessed for MSI status, two cases of MSI-H were associated with the c.973delA SGO1 variant. However, c.973delA SGO1 variant was also observed in four cases of microsatellite stable.
Conclusion Our study shows that SGO1 frameshift variants are not always associated with MSI status.
- stomach neoplasms
- gastrointestinal neoplasms
Data availability statement
All data relevant to the study are included in the article.
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Handling editor Runjan Chetty.
Contributors MI conceived the study. TS, MI, TT, SS, ST, MY, YH, SO, TF, HM, TO, SB, HS, MM and KS analysed and interpreted the data. TS, MI, HS, MM and KS drafted the manuscript and revised it critically for important intellectual content. All authors read and approved the final manuscript.
Funding The present study was supported by the Japan Society for the Promotion of Science (KAKENHI grant no. 19K08392), the Takeda Science Foundation and Hamamatsu University School of Medicine (HUSM) Grant-in-Aid.
Competing interests None declared.
Provenance and peer review Not commissioned; internally peer reviewed.
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