A case of microsatellite instability-high clinically advanced castration-resistant prostate cancer showing a remarkable response to pembrolizumab sustained over at least 18 months
Kosuke Shimizu, Takeshi Sano, Kei Mizuno, T. Sunada, N. Makita, H. Hagimoto, Takayuki Goto, A. Sawada, M. Fujimoto, K. Ichioka, Osamu Ogawa, Takashi Kobayashi, S. Akamatsu
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引用次数: 3
Abstract
Defective DNA mismatch repair genes can lead to microsatellite instability (MSI)-high status in prostate cancer (PC). Accumulation of replication errors in DNA leads to the production of abundant neoantigens, which could be targets for immune checkpoint inhibitors (CPIs). However, the incidence of MSI-high PC is low, and not all patients show a satisfactory therapeutic response to CPIs. Here, we present the case of a patient with MSI-high castration-resistant PC who showed a remarkable and durable response to pembrolizumab. The patient was resistant to abiraterone, docetaxel, and cabazitaxel and was suffering from multiple tumor-associated or treatment-related complications, such as urinary tract infection, infective endocarditis, and uncontrollable prostatic hemorrhage. Soon after the start of pembrolizumab therapy, the patient showed a dramatic decrease in prostate-specific antigen from 35.67 ng/mL to an undetectable level and a remarkable reduction in the size of a massive prostate mass and lymph node metastases, with an absence of treatment-related complications. Specimens from the transurethral resection of prostate cancer during cabazitaxel treatment for control of prostate bleeding and also that from the prostate biopsy at initial diagnosis revealed MSI-high status. Immunohistochemistry showed loss of MSH2 and MSH6, and whole-exome sequencing revealed an approximate tumor mutation burden of 61 mutations/Mb as well as biallelic loss of MSH2. Pembrolizumab could show a significant effect even in a heavily treated patient with MSI-high advanced PC. Accumulation of detailed clinical and genomic information of cases of MSI-high PC treated with pembrolizumab is necessary for optimal patient selection.
期刊介绍:
Cold Spring Harbor Molecular Case Studies is an open-access, peer-reviewed, international journal in the field of precision medicine. Articles in the journal present genomic and molecular analyses of individuals or cohorts alongside their clinical presentations and phenotypic information. The journal''s purpose is to rapidly share insights into disease development and treatment gained by application of genomics, proteomics, metabolomics, biomarker analysis, and other approaches. The journal covers the fields of cancer, complex diseases, monogenic disorders, neurological conditions, orphan diseases, infectious disease, gene therapy, and pharmacogenomics. It has a rapid peer-review process that is based on technical evaluation of the analyses performed, not the novelty of findings, and offers a swift, clear path to publication. The journal publishes: Research Reports presenting detailed case studies of individuals and small cohorts, Research Articles describing more extensive work using larger cohorts and/or functional analyses, Rapid Communications presenting the discovery of a novel variant and/or novel phenotype associated with a known disease gene, Rapid Cancer Communications presenting the discovery of a novel variant or combination of variants in a cancer type, Variant Discrepancy Resolution describing efforts to resolve differences or update variant interpretations in ClinVar through case-level data sharing, Follow-up Reports linked to previous observations, Plus Review Articles, Editorials, and Position Statements on best practices for research in precision medicine.