Expression and prognosis analysis of mitochondrial ribosomal protein family in breast cancer

Breast cancer (BC) is characterized by high morbidity. Mitochondrial ribosomal protein (MRP) family participates in mitochondrial energy metabolism, underlying BC progression. This study aims to analyze the expression and prognosis effect of the MRP genes in BC patients. GEPIA2, UALCAN, cBioPortal, and MethSurv were used to demonstrate the differential expression, genomic alteration profiles, and DNA methylation of the MRP gene family in BC. Functional enrichment analysis and protein-protein interaction network construction were performed to understand the biological function. Based on 1056 TCGA samples with the transcriptional level of MRPs, Kaplan-Meier curves, Cox, and LASSO regression were applied to explore their prognostic effects. 12 MRPs were upregulated in BC, which were associated with gene amplification and DNA methylation. MRP genetic alteration occurred in 42% of BC patients, and amplification was the most frequent variation. Functioning in its entirety, the MRP family was involved in mitochondrial translational termination, elongation, translation, and poly(A) RNA binding. High expression of MRPL1, MRPL13, MRPS6, MRPS18C, and MRPS35, as well as low levels of MRPL16, and MRPL40 significantly indicated poor prognosis in BC patients. Thus, a novel MRP-based prognostic nomogram was established and verified with favorable discrimination and calibration. We not only provided a thorough expression and prognosis analysis of the MRP family in BC patients but also constructed an MRP-based prognostic nomogram. It was suggested that MRPs acted as biomarkers in individualized risk prediction and may serve as potential therapeutic targets in BC patients.