scholarly journals Real-world Concordance in Microsatellite Instability Status Between PCR-based Testing and Next-Generation Sequencing Assay for Solid Tumors

Author(s):  
Keitaro Shimozaki ◽  
Hideyuki Hayashi ◽  
Sara Horie ◽  
Akihiko Chida ◽  
Kai Tsugaru ◽  
...  

Abstract Background: Various malignancies exhibit high microsatellite instability (MSI-H) or mismatch repair deficiency (dMMR). The MSI-IVD kit, which can detect MSI status using a polymerase chain reaction (PCR)-based method, was approved as the first tumor-agnostic companion diagnostic for pembrolizumab in patients with MSI-H solid tumors in Japan. Recently, next-generation sequencing (NGS), which can also detect MSI-H/dMMR, has been made clinically available. However, the real-world concordance in MSI-H/dMMR between the PCR-based testing and NGS is yet to be thoroughly investigated.Methods: A retrospective study was conducted to evaluate the utility of MSI testing using PCR-based testing and NGS assay in patients eligible for both MSI testing and any NGS platform. Co-primary endpoints included positive and negative predictive values of MSI-H/dMMR.Results: Between December 2018 and June 2020, 40 patients underwent both PCR-based MSI testing and NGS assay for MSI. Two patients with gastric neuroendocrine carcinoma and ovarian cancer were confirmed to have MSI-H/dMMR in both examinations. Among the 38 patients diagnosed as microsatellite stable by PCR-based testing, 2 (5.2%) with pancreatic cancer were diagnosed as MSI-H after NGS analyses. NGS had positive and negative predictive values of 100% (2/2) and 94.7% (36/38), respectively, for MSI-H, while the concordance between NGS and PCR-based testing was 94.9% (38/40).Conclusion: Similar to PCR-based MSI testing, NGS can be useful for evaluating MSI/MMR status in clinical practice and could be an important alternative method for detecting MSI-H/dMMR in the future.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Keitaro Shimozaki ◽  
Hideyuki Hayashi ◽  
Shigeki Tanishima ◽  
Sara Horie ◽  
Akihiko Chida ◽  
...  

AbstractVarious malignancies exhibit high microsatellite instability (MSI-H) or mismatch repair deficiency (dMMR). The MSI-IVD kit, a polymerase chain reaction (PCR)-based method, was the first tumor-agnostic companion diagnostic to detect MSI status in MSI-H solid tumors. Recently, next-generation sequencing (NGS), which can also detect MSI-H/dMMR, has been made clinically available; however, its real-world concordance with PCR-based testing of MSI-H/dMMR remains to be investigated. The co-primary end points included the positive and negative predictive values of MSI-H/dMMR. A retrospective analysis of 80 patients who had undergone both MSI testing and NGS between July 2015 and March 2021 was conducted. Five patients were confirmed to have MSI-H in both examinations. Among the 75 patients diagnosed as microsatellite stable (MSS) by PCR-based testing, one with pancreatic cancer was diagnosed as having MSI-H after NGS. One patient with pancreatic cancer was diagnosed as having MSS in both tests was found to have a mutation in MLH1 by NGS, which was confirmed as dMMR by IHC staining. NGS had positive and negative predictive values of 100% (5/5) and 98.7% (74/75), respectively, for MSI-H. The concordance between NGS and PCR-based testing was 98.8% (79/80). Thus, NGS can be useful for evaluating MSI/MMR status in clinical practice and can be an important alternative method for detecting MSI-H/dMMR in the future.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15566-e15566
Author(s):  
Hui Kong ◽  
Weijia Fang ◽  
Haibo Mou ◽  
Feng Xiao Chen ◽  
Lingxiang Liu ◽  
...  

e15566 Background: As a central component of PI3K/AKT pathway, AKT serves as an attractive target of anti-cancer strategy with various AKT inhibitors, which show great promise in phase I/II clinical trials. This study aimed to investigate AKT1/2/3 status in different types of cancers by using next generation sequencing (NGS). Methods: Formalin-fixed, paraffin-embedded (FFPE) tumor samples were collected from 10,010 Chinese patients with solid tumors and subjected to next-generation sequencing (NGS)-based 450 gene panel testing carried out by a College of American Pathologists (CAP) accredited and Clinical Laboratory Improvement Amendments (CLIA) certified laboratory. Genomic alterations, tumor mutational burden (TMB) values, and microsatellite instability (MSI) status were assessed with a mean coverage of 1000X, including single base substitutions, short and long insertion/deletions, copy number variations, gene fusions, and rearrangements. Genomic data and immune checkpoint inhibitors (ICIs) treatment outcome of a cohort of 1610 patients with solid tumors were derived from cBioPortal (MSKCC, Nat Genet. 2019). Results: AKT1/2/3 were found to be mutually exclusive with each other and accounted for 3.4% in this cohort. The frequencies of AKT1/2/3 variations were 1.1%, 1.6%, and 0.8%, respectively. The most common co-altered genes associated with AKT1/2/3 variations were TP53 (69.4%), PIK3CA (19.3%), KRAS (19%), CCNE1 (18.4%), CDKN2A (16.6%), and 11q13 (6.5%). AKT1/2/3 variations were significantly associated with higher TMB, and independent of MSI status. Outcome data from the MSKCC cohort showed that patients with AKT1/2/3 variations had a remarkable clinical benefit to ICIs treatment compared to patients with wild-type AKT1/2/3 in overall survival (OS) (NA vs 18 months, p = 0.009). Furthermore, AKT1/2/3 variations were independent risk factors of OS (HR: 0.55, 95%CI: 0.34-0.87, p = 0.012). Conclusions: The prevalence of AKT1/2/3 somatic alterations across different types of solid tumors in China was 3.4%. AKT1/2/3 variations were associated with an increased TMB and favorable response to ICIs, suggesting that A KT1/2/3 variations may be biomarkers for guiding anti-AKT agents and ICI treatment.


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