Long-term benefit of immunotherapy in a patient with squamous lung cancer exhibiting mismatch repair deficient/high microsatellite instability/high tumor mutational burden - A case report and literature review

Sep 24, 2026

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Genetic defects causing mismatch repair deficiency can produce microsatellite instability, which is common in colorectal and gastric cancers and in Lynch syndrome. Mismatch repair deficiency/high microsatellite instability (dMMR/MSI-H) is known to predict tumor responses to immune checkpoint inhibitors, yet evidence remains limited for non-small cell lung cancer (NSCLC). This report describes an advanced squamous lung cancer case with dMMR/MSI-H and high tumor mutational burden (TMB-H) showing durable benefit from immunotherapy, suggesting potential benefit for similar NSCLC patients.

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CategoryHealthcare

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Introduction

Case presentation

TYPE Case Report PUBLISHED 10 January 2023 DOI 10.3389/fimmu.2022.1088683 OPEN ACCESS EDITED BY Lin Qi, Hunan Key Laboratory of Tumor Models and Individualized Medicine, Central South University, China REVIEWED BY Yoshiaki Nakamura, National Cancer Center Hospital East, Japan Dahmane Oukrif, University College London, United Kingdom Stergios Boussios, King’s College London, United Kingdom Tiziana Venesio, Institute for Cancer Research and Treatment (IRCC), Italy *CORRESPONDENCE Ruilian Chen [chenruilian91430@gzucm.edu.cn](chenruilian91430@gzucm.edu.cn)[ ](chenruilian91430@gzucm.edu.cn)Xiaowei Ye [Billye983@yeah.net](Billye983@yeah.net) †These authors have contributed equally to this work and share ﬁrst authorship SPECIALTY SECTION This article was submitted to Cancer Immunity and Immunotherapy, a section of the journal Frontiers in Immunology RECEIVED 03 November 2022 ACCEPTED 20 December 2022 PUBLISHED 10 January 2023 CITATION Li N, Wan Z, Lu D, Chen R and Ye X (2023) Long-term beneﬁt of immunotherapy in a patient with squamous lung cancer exhibiting mismatch repair deﬁcient/high microsatellite instability/high tumor mutational burden: A case report and literature review. Front. Immunol. 13:1088683 . doi: 10.3389/fimmu.2022.1088683 Long-term beneﬁt of immunotherapy in a patient with squamous lung cancer exhibiting mismatch repair deﬁcient/high microsatellite instability/high tumor mutational burden: A case report and literature review Na Li 1†, Zixuan Wan 1†, Dongyan Lu 2, Ruilian Chen 2* and Xiaowei Ye 2* 1 First Clinical Medical College, Guangzhou University of Traditional Chinese, Guangzhou, China, 2 Department of Oncology, The First Afﬁliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, China Genetic mutations that render mismatch repair defective may result in microsatellite instability, which is common in colorectal carcinomas and gastric cancers as well as Lynch syndrome. Mismatch repair deﬁciency/high microsatellite instability (dMMR/MSI-H) predicts the tumor response to immune checkpoint inhibitors. However, few studies have evaluated the efﬁcacy of immune checkpoint inhibitors in non-small cell lung cancer (NSCLC) patients with dMMR/MSI-H. In this work, we present a patient with advanced squamous lung cancer with dMMR/MSI-H and a high tumor mutational burden (TMB-H) who obtained a long-term beneﬁt from immunotherapy. NSCLC patients with dMMR/MSI-H/TMB-H may thus beneﬁt from immune checkpoint inhibitors. KEYWORDS mismatch repair deﬁciency, high microsatellite instability (MSI-H), high tumor mutational burden, squamous lung cancer, immunotherapy Frontiers in Immunology 01 [frontiersin.org](frontiersin.org) Introduction Lung cancer is one of the most common cancers worldwide and has the highest mortality of all cancers (1). Immunotherapy has effectively treated many solid tumors. Programmed cell death-protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors have increased the 5-year survival rate for non-small cell lung cancer (NSCLC) patients by 20-30% . However, it remains challenging to ﬁnd patients exhibiting long-term responses to immunotherapy in the present era of precision medicine. The predictive biomarkers of immune checkpoint inhibitor efﬁcacy include the tumor cell surface PD-L1 expression level, tumor mutational burden (TMB), mismatch repair deﬁciency/high microsatellite instability (dMMR/MSI-H), and tumor-inﬁltrating lymphocytes (2–4) . Defects in DNA mismatch repair may lead to microsatellite instability, and subsequently a high TMB (TMB-H) and PD-L1 overexpression. The presence of dMMR/MSI-H was ﬁrst detected in patients newly diagnosed with colorectal cancer. dMMR/MSI-H was closely associated with the immunotherapy response of solid tumors, particularly colorectal cancer, gynecological cancers, and gastric cancer (5–7) . Accordingly, pembrolizumab and nivolumab were approved for the treatment

FAQs

What biomarkers are emphasized in predicting immunotherapy response in this case report?

The report highlights dMMR/MSI-H and high tumor mutational burden (TMB-H) as predictive biomarkers for response to immune checkpoint inhibitors.

What type and stage of lung cancer is described?

The document presents an advanced squamous lung cancer case exhibiting dMMR/MSI-H and high TMB-H.

What clinical outcome does the patient achieve after immunotherapy?

The patient obtains a long-term, durable benefit from immunotherapy with an immune checkpoint inhibitor (toripalimab is mentioned in the report).

Sep 24, 2026

Uploaded by dhado