TEP1 (telomerase-associated protein 1) is a critical component of the telomerase ribonucleoprotein complex essential for chromosome 14 replication 1. Located on chromosome 14.2 2, TEP1 also functions as a structural component of vault particles, large cytoplasmic ribonucleoprotein complexes involved in intracellular transport 3. TEP1 localizes and stabilizes vault RNA within the vault ribonucleoprotein particle and binds telomerase RNA (TERC). Unlike hTERT, TEP1 shows constitutive expression across hematopoietic cell types and maintains stable expression during myeloid differentiation, suggesting a supporting rather than rate-limiting role in telomerase activity 4. Clinically, TEP1 has significant relevance in cancer biology. Genetic variations in TEP1, particularly rs1760904, are associated with decreased prostate cancer risk and longer telomere length, with certain genotypes protective against biochemical recurrence after radical prostatectomy 5. Additionally, TEP1 mutations occur in renal cell carcinomas (7.5% of primary cases), particularly in advanced clear-cell carcinomas with metastatic potential, suggesting involvement in late-stage tumorigenesis 6. TEP1 expression also correlates with multidrug resistance gene expression in melanoma cells 7, indicating broader implications in cancer progression and treatment resistance.