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Published on: February 24, 2014
Prevalence of DNA Mismatch Repair Deficiencies in Multiple Solid Tumor Types in China
Xiaohua Shi1, Xianghong Yang2, Jingping Yun3
1Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Aim:
Microsatellite instability (MSI) as a result of deficient deoxyribonucleic acid (DNA) mismatch repair (dMMR) is a key contributor to the development of tumors with a high mutation rate and cancer-specific neoantigens. dMMR identification can be beneficial for selection of immune checkpoint inhibitor (ICI) therapy-eligible patients. While multiple studies have focused on dMMR prevalence in colorectal cancer (CRC), fewer investigate the prevalence of dMMR in tumor types besides CRC, especially in Chinese patients. In this study, we aimed to determine the prevalence of dMMR in China across five gastrointestinal and gynecological tumor types.
Methods:
Tissue samples from Chinese patients with advanced endometrial, ovarian, cervical, biliary tract, or gastric metastatic or unresectable solid tumors were tested for dMMR status using immunohistochemistry with the Ventana MMR RxDx panel. Data were analyzed to determine the prevalence of dMMR for each tumor type.
Results:
A total of 748 patients were included in the study, representing five tumor types. Prevalence of dMMR varied across tumor types, with an overall prevalence of 9.4%. Patients with endometrial tumors had the highest proportion of patients with dMMR at 49/164 (29.9%). Patients with cervical tumors had the lowest prevalence of dMMR with 6/221 (2.7%) patients. The prevalence of dMMR was similar across most demographic characteristics. In the dMMR population, co-occurring MLH1 and PMS2 protein loss across all tumor types was observed most commonly, in 48/70 (68.6%) patients.
Conclusions:
These data highlight the importance of dMMR testing in patients with advanced solid tumors in China to optimize biomarker testing and treatment decisions.
Insights
Deficient DNA mismatch repair (dMMR) prevalence varies across advanced solid tumors in Chinese patients. Endometrial tumors showed the highest dMMR rates, emphasizing the need for dMMR testing for treatment decisions.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Biomarkers
Background:
- Deficient DNA mismatch repair (dMMR) drives microsatellite instability (MSI), leading to high tumor mutation rates and neoantigens.
- dMMR identification is crucial for selecting patients eligible for immune checkpoint inhibitor (ICI) therapy.
- Limited data exists on dMMR prevalence in non-colorectal cancers, particularly in Chinese populations.
Purpose of the Study:
- To determine the prevalence of dMMR in five specific gastrointestinal and gynecological tumor types in Chinese patients.
- To provide insights into dMMR status across diverse advanced solid tumors in China.
Main Methods:
- Immunohistochemistry using the Ventana MMR RxDx panel was employed to test tissue samples from 748 Chinese patients.
- Tumor types included advanced endometrial, ovarian, cervical, biliary tract, and gastric cancers.
- Data analysis focused on determining dMMR prevalence for each tumor type.
Main Results:
- Overall dMMR prevalence was 9.4% across the five tumor types.
- Endometrial tumors exhibited the highest dMMR prevalence (29.9%), while cervical tumors had the lowest (2.7%).
- MLH1 and PMS2 protein loss was the most common dMMR alteration (68.6%) in the dMMR population.
Conclusions:
- dMMR testing is important for advanced solid tumors in China.
- These findings aid in optimizing biomarker testing and informing treatment decisions for Chinese cancer patients.
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