XBP1s Mediates Cross-resistance to Combination Treatment of CDK4/6 Inhibitors plus Endocrine Therapy in Breast Cancer.

ABSTRACT: CDK4/6 inhibitors combined with endocrine therapy is the standard treatment for patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC). However, the inevitable development of treatment resistance and lack of approved biomarkers for predicting therapeutic efficacy remain urgent concerns. This study indicates that XBP1 is prominently and specifically expressed in HR+/HER2- breast cancer, and correlated with unfavorable response and poor progression-free survival in patients with MBC receiving the combined therapy. XBP1s, a transcriptionally active spliced form of XBP1, accelerates tumor progression by facilitating cell proliferation and G1/S transition, and attenuates the efficacy of palbociclib and fulvestrant.

SUBMITTER: Sang Y 

PROVIDER: S-EPMC12667467 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature