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Acquired ESR1 Mutations

Meaning

Acquired ESR1 mutations are specific genetic alterations in the Estrogen Receptor 1 gene that develop somatically within tumor cells, meaning they are not inherited but emerge later in life. These somatic changes are particularly relevant in estrogen receptor-positive breast cancer, often manifesting as a mechanism of resistance during or after treatment with endocrine therapies. The presence of these mutations is a critical factor in determining subsequent clinical management strategies, as they alter the tumor’s response to hormone-blocking agents. Identifying these acquired genetic shifts through advanced genomic sequencing is paramount for personalizing therapy in metastatic disease.