ABCC11

Abstract: International mortality and frequency rates for breast cancer seem to be associated with the frequency of the allele for wet-type cerumen. A preliminary retrospective case-control study in California indicates that phenotypically wet-type cerumen is found in Japanese women with breast cancer more often than in healthy Japanese women. Findings support the hypothesis that the apocrine system's genetically determined variation may influence susceptibility to breast cancer.

Abstract: Background International mortality and frequency rates for breast cancer have been associated with the wet type of human earwax. It was recently found that earwax type is determined by a single nucleotide polymorphism (SNP), 538G>A (Gly180Arg), in ABCC11. The G allele determines the wet type of earwax as a Mendelian trait with a dominant phenotype. The present study examined the association between the frequency rate of breast cancer and the frequency of the G allele of ABCC11. Patients and methods Using blood samples from patients with invasive breast cancer (n = 270) and control volunteers (n = 273), the 538G>A SNP in ABCC11 was genotyped using the SmartAmp method. Results The frequency of the G allele in breast cancer patients was higher than that in healthy controls. The odds ratio for the genotypes (G/G+G/A) to develop breast cancer was estimated to be 1.63 (p-value = 0.026), suggesting that the G allele in ABCC11 is associated with breast cancer risk. Conclusion This study showed that Japanese women with wet earwax have a higher relative risk of developing breast cancer than those with dry earwax. The ABCC11 SNPs that determine these phenotypes should be further investigated in order to obtain insights into the mechanisms by which breast cancer develops and progresses.

Abstract: Axillary osmidrosis (AO) is caused by apocrine glands secretions that are converted to odouriferous compounds by bacteria. A potential link between AO and wet earwax type has been implicated by phenotype-based analysis. Recently, a non-synonymous single nucleotide polymorphism (SNP) 538G> A (Gly180Arg) in the human adenosine triphosphate (ATP)-binding cassette (ABC) transporter ABCC11 gene was found to determine the type of earwax. In this context, we examined a relationship between the degree of AO and the ABCC11 genotype. We have genotyped the SNP 538G> A in a total of 82 Japanese individuals (68 volunteers and 14 AO patients) by both DNA sequencing and the recently developed Smart Amplification Process (SmartAmp). The degree of AO in Japanese subjects was associated with the genotype of the ABCC11 gene as well as wet earwax type. In most AO patients investigated in this study, the G/G and G/A genotypes well correlated with the degree of AO, whereas A/A did not. The specific SmartAmp assays developed for this study provided genotypes within 30 min directly from blood samples. In East Asian countries, AO is rather infrequent. Although the judgement of the degree of AO prevalence is subjective, the SNP 538G> A in ABCC11 is a good genetic biomarker for screening for AO. The SmartAmp method-based genotyping of the ABCC11 gene would provide an accurate and practical tool for guidance of appropriate treatment and psychological management for patients.

Abstract: This report describes the volatile organic compounds (VOCs) associated with human cerumen (earwax) and the effects of ethnicity/race and variation on the ATP-binding cassette, sub-family C, member 11 gene (ABCC11). A single nucleotide polymorphism (SNP) in ABCC11 affects the cerumen VOC profiles of individuals from African, Caucasian, and Asian descent. Employing gas chromatography/mass spectrometry (GC/MS) we have identified the nature and relative abundance of cerumen VOCs from 32 male donors. Our results show that cerumen contains a complex mixture of VOCs and that the amounts of these compounds vary across individuals as well as across ethnic/racial groups. In six of the seven compounds whose detected concentrations were found to be statistically different across groups, individuals of African descent (AfD) > Caucasian descent (CaD) > Asians descent (AsD). Our findings also reveal that ABCC11 genotype alone does not predict the type and relative levels of volatiles found in human cerumen, and suggest that other biochemical pathways must be involved. Examination of the composition and diversity of external auditory canal microbiota in a small subset of our subject population revealed that the ear microbiota may not be directly correlated with either ethnic group membership or ABCC11 genotype.