Aims: Serotonin (5-hydroxytryptamine 3; 5-HT(3)) receptors are involved in chemotherapy-induced nausea and vomiting (CINV), and 5-HT(3) antagonists are part of the 'gold standard' antiemetic treatment during chemotherapy. We investigated the correlation of common variants in 5-HT(3) receptor subunit genes with the occurrence of CINV.
Materials & methods: A total of 110 previously characterized chemotherapy-naive women with primary breast cancer treated with anthracycline-containing chemotherapy served as a study group for mutational analysis by direct sequencing. Eight common SNPs in the 5-HT(3) receptor genes, HTR3A, HTR3B, HTR3D and HTR3E, were selected for association analysis.
Results: A nonsynonymous variant in HTR3D, p.G36A (rs6443930), was found to be over-represented in nonresponders, assuming a log-additive inheritance model (p = 0.048). Cox proportional regression analysis resulted in a hazards ratio of 0.36 for homozygous carriers of the C allele to vomit within 24 h after first chemotherapy administration (p = 0.049).
Conclusion: Our data supports the hypothesis that 5-HT(3) receptors play an important role in the pathogenesis of CINV. Along with previously identified HTR3 polymorphisms, the HTR3D p.G36A variant could also contribute to facilitating individual risk predictions.