Clinicopathological characteristics of human epidermal growth factor receptor-2 1+ cases in breast cancer
Main Article Content
Keywords
Breast Neoplasms, Gene Amplification, College of American Pathologists, Immunohistochemistry
Abstract
Abstract
Background: The expression of the HER2 oncogene has a specific prognostic and therapeutic objective in breast cancer care. Low gene expression, called HER2-low implies the possibility of being a candidate for targeted therapy. However, there is significant variability in its interpretation, hence the importance of emphasizing its proper identification and reporting.
Objective: To estimate the proportion of cases confirmed as HER2 1+ among biopsies previously reported as HER2 1+, and to describe their clinicopathological characteristics, as well as the interobserver agreement in their classification.
Materials and methods: Observational, retrospective, and analytical study of cases previously diagnosed as HER2-negative score 1+, which were reviewed by 2 independent pathologists.
Results: 351 cases were included, with a mean age of 59.56 years. The histological subtypes were invasive ductal carcinoma NOS (70.66%), histological grade 2 (56.92%), and SBR score 6 (41.82%), associated in 89.17% of cases with hormone receptor expression. There was agreement for the HER2-low diagnosis in 78.91% of cases, with a Cohen’s kappa simple of 0.62, which is similar to some studies documented in the literature.
Conclusions: Agreement in the interpretation of HER2-low increases when it is performed by at least 2 pathologists; likewise, proper handling of surgical specimens in the pre-analytical phase is vital for optimal assessment, as this has a direct impact on current prognosis and treatment.
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