Objective: This study aims to explore the expression of Structural Maintenance of Chromosome 1A (SMC1A) in breast cancer, and analyze its correlation with clinical pathologic features and its influence on apoptosis in breast cancer cells. Methods: The study first analyzed the expression differences of SMC1A mRNA in breast cancer and healthy breast tissues and their prognostic significance using The Cancer Genome Atlas (TCGA) database. It then involved collecting tumor and adjacent non-tumor tissue samples from 48 breast cancer patients at the First Affiliated Hospital of Nanjing Medical University from January to December 2023. We utilized real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) to assess SMC1A expression and its correlation with clinical pathologic traits. Additionally, by downregulating SMC1A expression in the MCF-7 breast cancer cell line, apoptosis-related protein changes were recorded. Results: Analyses showed a significant increase in SMC1A mRNA levels in breast cancer tissues compared to normal tissues, which also correlated with poorer cancer prognosis. Clinical verification indicated a higher expression of SMC1A in cancer tissues than in adjacent non-tumor tissues, correlating with TNM stage, lymph node involvement, and degree of pathological differentiation. Downregulation of SMC1A via siRNA1 in MCF-7 cells notably increased Cleaved-caspase3, Cleaved-caspase9, and BAX levels and decreased BCL2 levels. Conclusion: SMC1A is overexpressed in breast cancer tissues, correlating with disease progression and pathological differentiation. Early mechanistic investigations indicate that reducing SMC1A may promote apoptosis in breast cancer cells, suggesting its regulatory role could be critical in mitigating breast cancer progression.