Breast cancer (BC) is the most common type of cancer and the second leading cancer-related cause of death in women worldwide. Endocrine therapy is an effective therapeutic approach for estrogen receptor (ER)-positive breast cancer; however, in many cases, tumor regrowth occurs after the therapy and the tumor becomes unresponsive anymore. While some gene mutations contribute to the resistance in some patients, the underlying causes of the resistance to endocrine therapies are mostly

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... In this study, we utilized our recently developed statistical approach to investigate the dynamic behavior of gene expression during the development of endocrine resistance and identified a novel group of genes that can be crucial to the development of resistance in BC. The expression of these genes is not only altered in cell models during the endocrine resistance development but also significantly changed in endocrine-resistant patients. Surprisingly, this group of genes was also identified as a group of key candidate genes in triple-negative breast cancer (TNBC), suggesting that endocrine resistance and TNBC share the same mechanisms during their development. Our findings explain some of the genetic underlying reasons for endocrine resistance and provide the potential to develop novel common therapeutic approaches against endocrine-resistant BC and TNBC.