Objectives: Tamoxifen is considered to be the most widely used adjuvant therapy for hormone receptor positive breast cancer in premenopausal women. However, it is reported that nearly 30% of patients receiving tamoxifen therapy have shown reduced or no benefits. This may be due to the high inter-individual variations in the CYP2D6 gene that is involved in tamoxifen metabolism. The CYP2D6*10 gene variant (rs1065852C>T) is reported to be commonly found in Asian and South Asian populations. The present study was undertaken to design a novel pharmacogenetic assay (Single step-Tetra Arms Polymerase Chain Reaction) for the identification of the CYP2D6*10 variant and implement the designed assay by genotyping a cohort of breast cancer patients. Results: The novel assay was successfully designed, optimized and validated using Sanger sequencing. Blood samples from 70 patients were genotyped. The following bands were observed in the gel image: Control band at 454 bp; band for C allele at 195 bp; band for T allele at 300 bp. The genotype frequencies for the CYP2D6*10 (rs1065852C>T) variant were: CC-24.28% (17/70), CT-75.71% (53/70), TT-0% (0/70). The allele frequencies were: T-allele-37.86% and C-allele-62.14%.

Opioid use disorder is a major global-scale social issue affecting public health. Opioid use is a major concern due to its high potential for addiction and dependence, contributing to substancerelated disorders. Genetic and environmental factors contribute to the predisposition to opioid use disorders (OUD). The opioidergic, dopaminergic, and GABAergic systems are the primary systems involved in the onset of OUD. Consequently, this narrative review aims to document the association between the genes and their variants identified through the studies related to these key systems, along with current epigenetic interventions in OUD. Genetic associations play a prominent role in OUD, with single-nucleotide variants identified in OUD-affected populations. Previous research indicates that the OPRM1, OPRD1, OPRK1, PDYN, OPRL1 and POMC genes from the opioidergic system; the DRD1, DRD2, DRD3, DRD4, ANKK1 and COMT genes from the dopaminergic system, and the GABRA2, GABRB3, GABRG2, GAD1 and GAD2 genes from the GABAergic system are associated with the phenotypes of OUD in different ethnicities. In addition, the accumulated evidence suggests that chronic opioid use is associated with epigenetic changes in the DNA through post-translational histone modifications and DNA methylation processes. Although many candidate-gene associations have been proposed for OUD, a considerable number of studies have small sample sizes,

Methamphetamine is a highly addictive stimulant with severe health and psychosocial consequences. Over recent decades, genetic and molecular research on methamphetamine use disorders has expanded considerably, yet a comprehensive synthesis of this growing body of literature is lacking. This study conducted a bibliometric analysis to map the scientific landscape of genetic and molecular biology research on methamphetamine use, identifying key contributors, influential publications, publication trends, and co-occurring keywords and citations. A systematic search of the Scopus database retrieved 1550 documents. After applying the inclusion criteria and manual screening, 449 peer-reviewed articles published between 1993 and 2025 were included. Performance analysis and scientific mapping were conducted using VOSviewer software through bibliographic coupling and keyword co-occurrence. The study followed the BIBLIO checklist for reporting bibliometric reviews in biomedical literature. Publication output increased markedly after 2005, peaking in 2022, followed by a decline that may reflect a shift in research priorities. The United States, China, and Japan emerged as leading contributors, underscoring their significant investment in addiction and molecular research. Keyword co-occurrence revealed strong emphasis on addiction, dopamine, neurotoxicity, gene expression, and genetic polymorphisms, highlighting their central role in the pathophysiology of methamphetamine use disorders. This bibliometric analysis demonstrates substantial growth and influence of genetic research on methamphetamine use. Despite a recent decline in publications, the field provides a solid foundation for future interdisciplinary research and funding priorities in addiction genetics.