: A Potential Biomarker Related to Prognosis, Chemoresistance, and Expression of Microenvironmental Chemokine in HR-Positive Breast Cancer.

is significantly elevated in various malignancies. However, the clinical significance of in hormone receptor (HR)-positive (HR+) breast cancer remains unclear. We evaluated expression in different databases and validated assay by RT-PCR and western blot among HR+ breast cancer. The correlations between level and tumor-immune were calculated. Mutational landscape, enriched signaling pathways, and drug sensitivity analyses were also assessed between high and low-expression groups. was upregulated in HR+ breast cancer, and high expression was significantly linked with poor prognosis. was correlated with the expression and function of different immune cells. The low group showed sensitivity to paclitaxel and docetaxel, while the high-expression group showed sensitivity to doxorubicin. CTLA4 and PD-L1 were more sensitive in high- group. It is involved in a range of pathways and might behave as a novel biomarker of prognostic value for the immune environment and drug sensitivity in HR+ breast cancer.