RPL4 encodes ribosomal protein L4, a structural component of the large ribosomal subunit essential for protein synthesis 1. Beyond its canonical ribosomal function, RPL4 plays significant roles in cancer biology through the RPL4-MDM2-p53 regulatory axis. In this pathway, RPL4 normally binds to MDM2, preventing MDM2-mediated ubiquitination and degradation of the tumor suppressor p53 23. When RPL4 expression is disrupted by oncogenic proteins like CCT8 in colorectal cancer or PRC1 in ovarian cancer, the reduced RPL4-MDM2 complex formation leads to enhanced p53 ubiquitination and degradation, promoting tumor progression 23. RPL4 expression is upregulated in brain capillaries of Alzheimer's disease patients, specifically at the blood-brain barrier, correlating with increased protein processing machinery 1. In hepatocellular carcinoma, RPL4 is regulated by the lncRNA SNHG7/miR-122-5p axis and serves as a target for cancer progression 4. Additionally, RPL4 interacts with TTC22 to enhance WTAP mRNA stability and translation, promoting m6A-mediated gene regulation and colon cancer metastasis 5. RPL4 has been identified as a stable reference gene in cardiac disease studies and shows differential expression patterns in various cancer contexts 678.