LAPTM4B (lysosomal protein transmembrane 4 beta) is an oncogene that functions as a critical regulator of lysosomal metabolism and cellular survival pathways 1. The protein promotes tumor cell proliferation, invasion, metastasis, and resistance to apoptosis across various solid tumors 1. Mechanistically, LAPTM4B counteracts ferroptosis by preventing ubiquitin-proteasome degradation of SLC7A11, the cystine-glutamate antiporter essential for cellular antioxidant defense 2. In hepatocellular carcinoma, LAPTM4B is transcriptionally activated by HDAC2 and promotes autophagy-associated malignant progression 3. The protein also plays a crucial role in hematopoietic stem cell regulation through the mTOR pathway, where EVI1-mediated upregulation of LAPTM4B drives abnormal proliferation in myeloid malignancies 4. Clinically, LAPTM4B exhibits significant genetic polymorphism with two major alleles (*1 and *2) that show differential cancer susceptibility patterns. The LAPTM4B*2 allele increases risk for malignant melanoma and primary liver cancer 56, while paradoxically decreasing prostate cancer risk 7. High LAPTM4B expression serves as a poor prognosis marker across multiple cancer types, highlighting its potential as both a therapeutic target and prognostic indicator 1.