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Kohlruss M, Chakraborty S, Hapfelmeier A, Jesinghaus M, Slotta-Huspenina J, Novotny A, Sisic L, Gaida MM, Ott K, Weichert W, Pfarr N, Keller G. Low microsatellite instability: A distinct instability type in gastric cancer? J Cancer Res Clin Oncol 2023; 149:17727-17737. [PMID: 37819581 PMCID: PMC10725348 DOI: 10.1007/s00432-023-05430-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023]
Abstract
PURPOSE We recently showed that low microsatellite instability (MSI-L) is associated with a good response to platinum/5-fluorouracil (5-FU) neoadjuvant chemotherapy (CTx) in gastric cancer. The purpose of this study was to characterize the instability pattern and to investigate an association of MSI-L tumors with mutations in genes of DNA repair pathways and with total tumor mutation burden (TMB). METHODS MSI patterns were compared between 67 MSI high (-H) and 35 MSI-L tumors. Whole-exome sequencing was performed in 34 microsatellite stable (MSS) and 20 MSI-L tumors after or without neoadjuvant CTx. RESULTS Of the 35 MSI-L tumors, 33 tumors had instability at a dinucleotide repeat marker. In the homologous recombination (HR) pathway, 10 of the 34 (29%) MSS and 10 of the 20 (50%) MSI-L tumors showed variants (p = 0.154). In the DNA damage tolerance pathway, 6 of the 34 (18%) MSS and 7 of the 20 (35%) MSI-L tumors had variants (p = 0.194). The HR deficiency score was similar in both tumor groups. TMB was significantly higher in MSI-L compared to MSS tumors after CTx (p = 0.046). In the MSS and MSI-L tumors without CTx no difference was observed (p = 1.00). CONCLUSION MSI-L due to instability at dinucleotide repeat markers was associated with increased TMB after neoadjuvant CTx treatment, indicating sensitivity to platinum/5-FU CTx. If confirmed in further studies, this could contribute to refined chemotherapeutic options including immune-based strategies for GC patients with MSI-L tumors.
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Affiliation(s)
- Meike Kohlruss
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany
| | - Shounak Chakraborty
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany
| | - Alexander Hapfelmeier
- Institute of AI and Informatics in Medicine, School of Medicine, Technical University of Munich, Munich, Germany
| | - Moritz Jesinghaus
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany
- Institue of Pathology, University of Marburg, Marburg, Germany
| | - Julia Slotta-Huspenina
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany
| | - Alexander Novotny
- Department of Surgery, TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Leila Sisic
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Matthias M Gaida
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany
- Institute of Pathology, University Medical Center Mainz, JGU-Mainz, Mainz, Germany
- TRON-Translational Oncology at The University Medical Center of The Johannes Gutenberg University gGmbH, Mainz, Germany
| | - Katja Ott
- Department of Surgery, Klinikum Rosenheim, Rosenheim, Germany
| | - Wilko Weichert
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany
- Institute of Pathology, German Cancer Consortium [DKTK], Partner Site Munich, Munich, Germany
| | - Nicole Pfarr
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany
| | - Gisela Keller
- Institute of Pathology, TUM School of Medicine, Technical University of Munich, Trogerstr. 18, 81675, Munich, Germany.
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