51. Double Heterozygosity for Germline Mutations in Chinese Breast Cancer Patients.
- Author
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Kwong, Ava, Ho, Cecilia Y. S., Au, Chun-Hang, and Ma, Edmond S. K.
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PUBLIC health surveillance , *BRCA genes , *RESEARCH funding , *BREAST tumors , *CANCER patients , *ONCOGENES , *GENETIC mutation , *WOMEN'S health , *PHENOTYPES - Abstract
Simple Summary: About 5–10% of breast cancers are related to heredity. Very often, affected individuals will carry only a single mutation defect in any of the hereditary breast and ovarian cancer syndrome (HBCO)-related genes. Breast cancer patients who are double heterozygous (DH) for different HBCO-related genes are rare. In this study, we provide real-world data for the Chinese population based on our high-risk referral patients from the Hong Kong Hereditary Breast Cancer Family Registry. DH germline mutations were identified in nine patients (0.25%) and associated with a higher prevalence of bilateral breast cancers in the Chinese population compared to other populations. A more stringent surveillance program and possibly a more aggressive treatment plan for all DH families could be tailored to specific family needs in the local area. Double pathogenic mutations occurring in an individual are considered a rare event. The introduction of a multiple-gene panel at Hong Kong Hereditary Breast Cancer Family Registry has allowed the identification of pathogenic variants in multiple genes, providing more information on clinical management and surveillance to the proband and their family members. Breast cancer patients who are double heterozygous (DH) for different hereditary breast and ovarian cancer syndrome (HBCO)-related genes were identified from a cohort of 3649 Chinese patients. Nine patients (0.25%) were observed to have germline DH mutations in ATM, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MSH6, PALB2, and TP53. Three probands were diagnosed with unilateral breast cancer, two patients were diagnosed with bilateral breast cancer, and four patients had multiple primary cancers. The median age for breast cancer diagnosis was an early age of 36 years. Chinese DH carriers did not show worse phenotypes or have a significantly downhill clinical presentation. However, seven out of nine (77.8%) of our DH carriers harbored a BRCA1 mutation, and four of them (44.4%) developed bilateral breast cancer, suggesting Chinese DH individuals may have a higher chance of having bilateral breast cancer than other populations (p = 0.0237). [ABSTRACT FROM AUTHOR]
- Published
- 2024
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