First, we divided the TCGA data of stage II Luminal A breast cancer patients into C1orf50-high and C1orf50-low groups and performed Gene Set Enrichment Analysis (GSEA) using the Molecular Signatures Database (MSigDB) hallmark gene sets, and found a significant increase in the MITOTIC_SPINDLE gene set, which is related to the cell cycle. Here, C1orf50 is linked to breast cancer.