Genetic Variation and the Role of Multigene Panel Testing for Hereditary Breast Cancer: A Single-Institution...

Area of Science:

• Oncology
• Genetics
• Medical Diagnostics

Background:

• Breast cancer is a leading cause of cancer death in women.
• Hereditary breast cancer can be caused by mutations beyond BRCA1 and BRCA2.
• Accurate genetic diagnosis is crucial for patient management.

Purpose of the Study:

• To evaluate the diagnostic yield of expanded genetic panel testing for hereditary breast cancer.
• To identify pathogenic variants in breast cancer patients beyond BRCA1/2 mutations.

Main Methods:

• Retrospective analysis of 1568 breast cancer patients diagnosed between 2015-2018.
• Genetic testing was performed on 26% of the study population.
• Pathogenic variants were identified according to National Comprehensive Cancer Network (NCCN) Guidelines.

Main Results:

• 8% of patients who underwent genetic testing carried a pathogenic variant.
• BRCA1 and BRCA2 mutations accounted for 3.4% of cases.
• Other prevalent pathogenic variants were identified in the remaining cases.

Conclusions:

• Expanded genetic panels increase the detection rate of pathogenic variants compared to BRCA1/2 testing alone.
• Identifying additional mutations impacts targeted treatment and prevention.
• Physicians should consider re-testing with expanded panels for patients with prior negative BRCA1/2 results.