Establishment of a gastric cancer cell line with high microsatellite instability, OCUM‐13, derived from Borrmann type‐2 primary tumor

Gastric cancer (GC) with microsatellite instability (MSI) has been reported to be sensitive to immunotherapy, however some of GC cases with MSI remain resistant to immunotherapy. Cancer cell lines showing MSI might be useful for the analysis of mechanisms of immunotherapy, while only a few GC cell lines with MSI are available so far. In this study, we established a unique GC cell line with MSI, OCUM‐13, from a primary GC with abundant tumor‐infiltrating lymphocytes. MSI assay indicated that OCUM‐13 cells as well as the primary tumor showed a band shift in more than 3 of 5 microsatellite loci, suggesting that OCUM‐13 did have high MSI. The subcutaneous inoculation of OCUM‐13 cells into mice performed tumor formation. Insulin‐like growth factor 1 receptor inhibitor decreased the growth of OCUM‐13 cells. The newly established cell line with MSI, OCUM‐13, might be useful for the analysis of cancer therapy for GC with MSI.