CCNA2 and bladder transitional cell carcinoma: Then, we also investigated the biological role of MEN1 in BLCA using Gene Set Enrichment Analysis (GSEA) based on mRNA expression data from the TCGA database, which showed that high levels of MEN1 were positively correlated with cell cycle-related genetic features (Fig. 1E), including cyclin-dependent kinase 1 (CDK1), cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), cyclin A2 (CCNA2), cyclin B1 (CCNB1), and cyclin E1 (CCNE1) (Fig. 1F).