CD44 and SLC1A2 are commonly regulated but do not form a fusion transcript in ER+ breast cancer

Endocrine therapy (ET) is essential for managing ER+ HER2− breast cancer; however, resistance remains a significant clinical challenge. This study investigated whether CD44-SLC1A2 gene fusions, reported in gastrointestinal malignancies, contribute to ET resistance mechanisms in breast cancer. Although no CD44-SLC1A2 fusions were detected, high expression of CD44 and SLC1A2 was associated with poor survival outcomes and identified a therapy-resistant subpopulation sustained by aspartate and glutamate metabolism, highlighting potential metabolic vulnerabilities for future therapeutic intervention.