Overcoming Trastuzumab Resistance in SK-BR-3 Tumorspheres with Tamoxifen

Trastuzumab resistance remains a significant challenge in treating HER2-positive breast cancer. Studies have shown that SK-BR-3 tumorspheres, which are enriched in quiescent cancer stem-like cells, exhibit enhanced EGFR/HER2 signaling and cytoplasmic estrogen receptor ? (ER?) expression, contributing to trastuzumab resistance. Tamoxifen, an ER? inhibitor, has been found to target these tumorspheres effectively, disrupting the crosstalk between ER? and EGFR/HER2 pathways, thereby overcoming resistance and reducing tumor growth.