1. Differentiating HER2-low and HER2-zero tumors with 21-gene multigene assay in 2,295 HR + HER2- breast cancer: a retrospective analysis
- Author
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Yoonwon Kook, Young-jin Lee, Chihhao Chu, Ji Soo Jang, Seung Ho Baek, Soong June Bae, Yoon Jin Cha, Gyungyup Gong, Joon Jeong, Sae Byul Lee, and Sung Gwe Ahn
- Subjects
Breast cancer ,HER2-low ,21-gene multigene assay ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Background HER2-positivity is an essential marker for therapeutic decisions, while HER2 expression is heterogenous. In recent years, there has been increasing recognition of a subgroup of breast cancer patients who have low levels of HER2 expression, also known as HER2-low because trastuzumab deruxtecan offers clinical benefit for patients with HER2-low metastatic breast cancer. Despite the growing interest in HER2-low breast cancer, there is limited research on how multigene assays can help differentiate between HER2-low and HER2-negative breast cancer. Among HR + HER2- breast cancer, we compared genomic characteristics between HER2-low and HER2-zero using the 21-gene assay. Methods A retrospective review of clinical records was performed in 2,295 patients who underwent Oncotype DX® test in two hospitals between 2013 and 2020. Patients were classified into two groups as the HER2-zero and HER2-low based on HER2 immunohistochemistry. In cases with HER2 2+, no amplification of HER2 gene was confirmed by silver in situ hybridization. High genomic risk was defined as cases with 21-gene recurrence score (RS) > 25. Multivariable binary logistic-regression analysis was performed. Results Of these, 944 (41.1%) patients were assigned to the HER2-zero group, while 1351 (58.9%) patients were assigned to the HER2-low group. The average Recurrence Score (RS) was found to be 17.802 in the HER2-zero breast cancer group and 18.503 in the HER2-low group, respectively (p-value
- Published
- 2024
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