Tamoxifen metabolism in breast cancer treatment: Taking the focus off the CYP2D6 gene

UDP-glucuronosyltransferase genetic variation in North African populations: a comparison with African and European data

BACKGROUND

Genetic variation in glucuronosyltransferases (UGT) is crucial in drug metabolism and risk of some diseases.

AIM

To examine genetic variation in UGT in North African populations.

SUBJECTS AND METHODS

Allele frequencies of SNPs UGT1A4^24Thr, UGT1A4^48Val, UGT2B15^85Tyr, UGT2B15^523Thr and UGT2B17 CNV deletion from Morocco, Algeria, Tunisia and Libya were compared to European and Sub-Saharan populations.

RESULTS

North Africans are the group with the highest genetic heterogeneity given by internal differences in the occurrence of UGT2B17 deletion, UGT1A4^48Val and UGT1A4 haplotypes. UGT2B15 SNPs differentiate Sub-Saharans from the rest of the populations.

CONCLUSION

North African populations show a high frequency of carriers of UGT2B15^523Thr, a variant linked to an increased risk of prostate cancer. High Atlas Moroccans and Algerians show low frequency of UGT2B17^del, a variant associated with high concentrations of testosterone and oestradiol.

Pharmacogenomics Guided-Personalization of Warfarin and Tamoxifen

The use of pharmacogenomics to personalize drug therapy has been a long-sought goal for warfarin and tamoxifen. However, conflicting evidence has created reason for hesitation in recommending pharmacogenomics-guided care for both drugs. This review will provide a summary of the evidence to date on the association between cytochrome P450 enzymes and the clinical end points of warfarin and tamoxifen therapy. Further, highlighting the clinical experiences that we have gained over the past ten years of running a personalized medicine program, we will offer our perspectives on the utility and the limitations of pharmacogenomics-guided care for warfarin and tamoxifen therapy.

The effect of CYP2D6 *10 polymorphism on adjuvant tamoxifen in Asian breast cancer patients: a meta-analysis

Objective

To evaluate the effect of CYP2D6 *10 polymorphism (C 100C>T, rs1065852) on clinical outcomes of female Asian breast cancer patients with tamoxifen adjuvant treatment.

Methods

Meta-analysis of retrospective cohort studies published in July 2017 was performed. Fifteen studies with 1,794 Asian breast cancer patients were included, using strict eligibility requirements. Associations of disease-free survival (DFS), overall survival (OS) and recurrence rate after tamoxifen intake, with CYP2D6 *10 polymorphism were investigated through random effects models.

Results

CYP2D6 *10 polymorphism was found to have effect on DFS and recurrence rate in various comparison models, but not on overall survival in the female Asian breast cancer patients.

Conclusion

In conclusion, our meta-analysis suggests that significant association of *10/*10 (TT) genotype with poorer DFS and recurrence exists in female Asian breast cancer patients with tamoxifen 20 mg/day adjuvant treatment. In the future, large and well-designed studies are required to illustrate the interactions of CYP2D6 genetic variants, including *10 polymorphism and tamoxifen response on female breast cancer patients.