SLC22A16 encodes a facilitative organic cation transporter that mediates bidirectional, partially sodium-dependent transport of carnitine and spermidine. It plays a role in carnitine secretion from testicular epididymal epithelium, contributing to spermatozoa maturation. Beyond its endogenous substrate roles, SLC22A16 functions as an adriamycin importer, transporting chemotherapeutic agents into cells. This transporter activity has clinical significance in cancer treatment: SLC22A16 is abundantly expressed in clear-cell ovarian adenocarcinoma (46.2% of cases) compared with other epithelial ovarian cancer histologies, and its expression correlates with potential adriamycin responsiveness 1. In endometrial cancer, SLC22A16 expression is regulated by progesterone, suggesting that progestins may enhance adriamycin sensitivity in SLC22A16-expressing endometrial carcinomas 2. Physical plasma treatment synergistically enhances doxorubicin cytotoxicity in melanoma cells through SLC22A16 upregulation 3. Genetic variation in SLC22A16 influences drug pharmacokinetics and clinical outcomes. Common polymorphisms (rs12210538) associate with doxorubicin exposure levels in Asian breast cancer patients 4 and with red blood cell carnitine depletion and hemolysis during storage 5. In acute myeloid leukemia, PSMB10 suppression enhances SLC22A16-mediated drug endocytosis, promoting chemotherapy-induced senescence and leukemia stem cell eradication 6, positioning SLC22A16 as a potential therapeutic target in drug-resistant hematologic malignancies.