RESUMO
The article discusses the importance of accurately distinguishing HER2-low from HER2-negative breast cancer, as novel ADCs have demonstrated activity in a large population of patients with HER2-low-expressing BC. While current guidelines recommend a dichotomous classification of HER2 as either positive or negative, the emergence of the HER2-low concept calls for standardization of HER2 testing in breast cancer, using currently available assays to better discriminate HER2 levels. This review covers the evolution and latest updates of the ASCO/CAP guidelines relevant to this important biomarker in breast cancer, including still-evolving concepts such as HER2 low, HER2 heterogeneity, and HER2 evolution. Our group presents the latest Mexican recommendations for HER2 status evaluation in breast cancer, considering the ASCO/CAP guidelines and introducing the HER2-low concept. In the era of personalized medicine, accurate HER2 status assessment remains one of the most important biomarkers in breast cancer, and the commitment of Mexican pathologists to theragnostic biomarker quality is crucial for providing the most efficient care in oncology.
RESUMO
Myoepithelioma is an infrequent benign tumor of the salivary glands, characterized by its composition of myoepithelial cells which can show different shapes and be arranged in various patterns with a well-circumscribed or encapsulated growth. This tumor commonly presents in adults as an asymptomatic swelling of the parotid gland, very rarely in minor salivary glands of children or adolescents, and even rarer in the buccal mucosa, with only six cases reported to date and only one of them presented in an adolescent. We present an additional case of myoepithelioma in the buccal mucosa of a 16-year-old male, with a novel clinical presentation as a non-submucosal exophytic mass. Immunohistochemically, neoplastic cells were positive for CK, S100, p63, and GFAP. The tumour was treated surgically, and the patient showed satisfactory evolution at 1 year of follow-up. The clinical and histopathological characteristics of the reported cases are discussed.
