CD274 and triple-negative breast carcinoma: A miRNA regulatory network targeting SLC7A11 was constructed in breast cancer and the SLC7A11-miR-148b-3p axis was tested via <i>in vitro</i> experiments in triple-negative breast cancer (TNBC) cell models (MDA-MB-231 and MDA-MB-468).<h4>Results</h4>Pan-cancer analysis revealed upregulation of SLC7A11 transcriptional expression in over 88% tumor types, and associations with established immunotherapy-related features, including tumor mutational burden, microsatellite instability, PD-L1 expression, and immune infiltration.