CYP2D6 gene polymorphisms and breast cancer risk in Moroccan population: A case-control study

CYP2D6 Genotyping for Optimization of Tamoxifen Therapy in Indonesian Women with ER+ Breast Cancer

Background: Certain CYP2D6 genotypes are linked to a lower efficacy of tamoxifen therapy. This study aimed to observe CYP2D6 polymorphisms and examine the impact of CYP2D6 genotyping among tamoxifen-treated breast cancer patients in Indonesia. Methods: 150 breast cancer participants were recruited. Buccal swab samples were collected; gDNA was extracted and genotyped using the qPCR method. Blood samples were collected, and measurement of tamoxifen metabolite levels was performed using UPLC-MS/MS. Results: 43.3% (n = 65) of participants were IMs. *10 was the most common haplotype (n = 89, 29.7%), followed by *36 (n = 73, 29.7%), making *10/*36 the most common diplotype (n = 34, 22.7%) in this study. The difference in endoxifen levels between the NM and IM-PM groups at baseline was statistically significant (p ≤ 0.001). A dose increase in tamoxifen to 40 mg daily successfully increased endoxifen levels in IMs to a similar level with NMs at baseline (p > 0.05) without exposing IMs to serious side effects. No statistically significant differences were observed between the 20mg group and the 40 mg group on the adjusted OS (p > 0.05) and the adjusted PFS (p > 0.05). Conclusions: Our study observed a considerably high proportion of CYP2D6 IMs. The dose adjustment of tamoxifen was proven to significantly and safely improve the level of endoxifen and survival.

Explore the distribution of (rs35742686, rs3892097 and rs1065852) genetic polymorphisms of cytochrome P4502D6 gene in the Moroccan population

Background

The CYP2D6 gene encodes a crucial enzyme involved in the metabolic pathways of many commonly used drugs. It is a highly polymorphic gene inducing an interethnic and interindividual variability in disease susceptibility and treatment response. The aim of this study is to evaluate the frequency of the three CYP2D6 most investigated alleles (CYP2D6*3, CYP2D6*4, and CYP2D6*10 alleles) in Morocco compared to other populations.

This study enrolled 321 healthy Moroccan subjects. CYP2D6 genotypes and allele frequencies were assessed using a restriction fragment length polymorphism–polymerase chain reaction genotyping method. The Principal Component Analysis (PCA) and dendrogram were conducted to evaluate genetic proximity between Moroccans and other populations depending on CYP2D6 allele frequencies.

Results

According to the current study, the results observed the homozygous wild type of the three studied SNPs were predominant among the Moroccan population, while 1.4% of Moroccans carried the CYP2D6*4 allele responsible for a Poor Metabolizer phenotype and associated with low enzyme activity which may induce a treatment failure. The PCA and cluster dendrogram tools revealed genetic proximity between Moroccans and Mediterranean, European and African populations, versus a distancing from Asian populations.

Conclusion

The distribution of CYP2D6 polymorphisms within Morocco follows the patterns generally found among the Mediterranean, European and African populations. Furthermore, these results will help to lay a basis for clinical studies, aimed to introduce and optimize a personalized therapy in the Moroccan population.

Frequencies of CYP2D6 genetic polymorphisms in Arab populations

CYP2D6 is a key drug-metabolizing enzyme implicated in the biotransformation of approximately 25% of currently prescribed drugs. Interindividual and interethnic differences in CYP2D6 enzymatic activity, and hence variability in substrate drug efficacy and safety, are attributed to a highly polymorphic corresponding gene. This study aims at reviewing the frequencies of the most clinically relevant CYP2D6 alleles in the Arabs countries. Articles published before May 2021 that reported CYP2D6 genotype and allelic frequencies in the Arab populations of the Middle East and North Africa (MENA) region were retrieved from PubMed and Google Scholar databases. This review included 15 original articles encompassing 2737 individuals from 11 countries of the 22 members of the League of Arab States. Active CYP2D6 gene duplications reached the highest frequencies of 28.3% and 10.4% in Algeria and Saudi Arabia, respectively, and lowest in Egypt (2.41%) and Palestine (4.9%). Frequencies of the loss-of-function allele CYP2D6*4 ranged from 3.5% in Saudi Arabia to 18.8% in Egypt. The disparity in frequencies of the reduced-function CYP2D6*10 allele was perceptible, with the highest frequency reported in Jordan (14.8%) and the lowest in neighboring Palestine (2%), and in Algeria (0%). The reduced-function allele CYP2D6*41 was more prevalent in the Arabian Peninsula countries; Saudi Arabia (18.4%) and the United Arab Emirates (15.2%), in comparison with the Northern Arab-Levantine Syria (9.7%) and Algeria (8.3%). Our study demonstrates heterogeneity of CYP2D6 alleles among Arab populations. The incongruities of the frequencies of alleles in neighboring countries with similar demographic composition emphasize the necessity for harmonizing criteria of genotype assignment and conducting comprehensive studies on larger MENA Arab populations to determine their CYP2D6 allelic makeup and improve therapeutic outcomes of CYP2D6- metabolized drugs.