Comprehensive Analysis of Mitochondrial Metabolism Related Molecular Subtypes and Prognostic Scoring Model Index Construction in Breast Cancer

Further stratification of breast cancer (BRCA) prognosis holds significant clinical value, while mitochondrial metabolism plays a crucial role in BRCA progression, though its specific mechanisms and targets remain unclear. In this study, we integrated clinical survival data to identify mitochondrial metabolism-associated genes (MMAGs) related to BRCA prognosis and developed an MMAG-based risk scoring system using univariate and multivariate Cox regression along with LASSO analysis. We evaluated the correlation between MMAG molecular subtypes, immune microenvironment infiltration, and clinicopathological characteristics, and performed single-cell sequencing analysis to characterize MMAG expression patterns across different BRCA cell subpopulations. Furthermore, in vitro experiments validated the function of MTDH, a key MMAG, demonstrating that its knockdown significantly inhibited BRCA cell proliferation and invasion, as supported by cell proliferation, colony formation, wound healing, and Transwell migration assays. Our results indicate that the MMAG-based scoring system effectively stratifies BRCA patients into high- and low-risk groups with independent prognostic value, and immune infiltration analysis revealed significant differences in the tumor microenvironment between risk groups. In conclusion, we developed a novel MMAG-based prognostic scoring system for BRCA and demonstrated its clinical relevance. Additionally, MTDH was identified as a key gene influencing BRCA progression, providing a potential therapeutic target for BRCA treatment.