ABCC11 encodes an ATP-dependent transporter of the ABC family that actively extrudes physiological compounds and xenobiotics from cells 1. The transporter mediates efflux of diverse lipophilic anions including glutathione S-conjugates (leukotriene C4), steroid sulfates (DHEAS, estrone 3-sulfate), glucuronides (estradiol 17-beta-D-glucuronide), bile acids (glycocholate, taurocholate), cyclic nucleotides (cAMP, cGMP), and chemotherapeutic agents like methotrexate and 5-fluorouracil 1. A critical non-synonymous SNP 538G>A (Gly180Arg) dramatically affects ABCC11 function, with the variant protein undergoing proteasomal degradation due to misfolding 2. This polymorphism determines earwax type: wild-type (G allele) produces wet earwax while the variant (A allele) produces dry earwax 23. ABCC11 plays essential roles in apocrine gland secretion, including transport of odorant precursors that contribute to axillary osmidrosis when metabolized by skin bacteria 45. The transporter also influences ear canal microbiota composition through genome-microbiome interactions 6. Clinically, ABCC11 polymorphisms serve as biomarkers for predicting chemotherapy efficacy, particularly for nucleoside-based anticancer drugs, and for diagnosing axillary osmidrosis 23.