Both poor and ultrarapid CYP2D6 metabolizers of tamoxifen have a worse prognosis for breast cancer compared with normal metabolizers after receiving a standard dose of tamoxifen.
From the perspective of the Chinese healthcare system, CYP2D6*10 pharmacogenetic testing was cost effective for postmenopausal women with ER-positive early breast cancer.
<b>Conclusion:</b><i>CYP2D6*10</i> pharmacogenetic-guided selective estrogen receptor modulator can be a cost-effective strategy in the Chinese patients with hormone receptor-positive breast cancer.
The purpose of the study was to determine the association between CYP2D6*10 (c.100C>T) genotype and attainment of the plasma steady-state Z-END minimal threshold concentration (MTC) in Indonesian women with breast cancer.
These results are consistent with the relatively few other large, population-based studies conducted to date that have not observed an increased risk of adverse BC outcomes associated with CYP2D6 inhibition.
Patients with certain CYP2D6 genetic polymorphisms and patients who receive strong CYP2D6 inhibitors exhibit lower endoxifen concentrations and a higher risk of disease recurrence in some studies of tamoxifen adjuvant therapy of early breast cancer.
This issue of Clinical Pharmacology & Therapeutics (CPT) includes the Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for using CYP2D6 genotyping to guide tamoxifen therapy for breast cancer patients.
From our review of published data we found that standardization of CYP2D6 genotype-phenotype classification is needed in order to ensure effective evaluation of associations between CYP2D6 polymorphisms and endoxifen concentrations and BC outcomes.
The relationship between the CYP2D6 polymorphisms and tamoxifen efficacy in adjuvant endocrine therapy of breast cancer patients in Chinese Han population.
Summary estimates of association, with or without bias adjustment, indicated no clinically important association between CYP2D6 genotype and breast cancer survival in tamoxifen-treated women.
In response to: Damkier P. Don't think twice it's all right: tamoxifen and CYP2D6 genotyping in the treatment of breast cancer patients.Pharmacogenomics 18(8), XXX (2017).
CYP2D6 have been intensively studied, but the role of CYP2C19 is less elucidated, and we studied the association of CYPC19 genotype and recurrence of breast cancer.
In this study, we investigated whether single nucleotide polymorphisms (SNPs) identified by genome-wide association study (GWAS) (MAP3K1, FGFR2, TNRC9, HCN1, and 5p12), and SNPs involved in the metabolism of estrogen (CYP19, COMT, ESR1, and UGT1A1), tamoxifen (CYP2C9, CYP2C19, CYP3A5, and CYP2D6), and chemotherapeutic agents (ABCB1, ALDH3A1, and CYP2B6) are associated with the prognoses of 414 hormone receptor (HR)-positive early breast cancers with negative or 1 to 3 nodal metastases.
Trials examining tamoxifen dose escalation and breast cancer outcome should be guided by endoxifen levels alone, without reference to CYP2D6 genotype or presence of hot flashes.Clin Cancer Res; 22(13); 3164-71.
In relation to CYP2D6 genotype, CYP2D6*10/*10 is more frequently observed in both Malaysian Malay (28.9%) and Chinese (57.1%) breast cancer patients, whereas CYP2D6*4/*10 is more frequently observed in Malaysian Indian (42.8%) breast cancer patients.