Evaluation of DRD۱ Gene Expression Pattern and rs۷۷۴۰۳۴۱۶۳ Genetic Polymorphism in Patients with Gastric Cancer: A Case-Control Study in Iran

Objective: Gastric cancer (GC) ranks among the most prevalent cancers of the gastrointestinal (GI) tract and is responsible for many cancer deaths annually. The etiology of GC is believed to result from the cumulative damaging effects of genetic, epigenetic, and environmental factors during the individual’s lifetime. Dopamine receptor D۱ (DRD۱) represents the most abundant dopamine receptor in the central nervous system (CNS). Several dopaminergic pathways depend on the receptor to convey stimulatory dopamine signals. The current project has been designed to assess the gene expression and polymorphism of DRD۱ (rs۷۷۴۰۳۴۱۶۳ A>T) among Iranian patients suffering from GC in Isfahan. Materials and Methods: ARMS PCR technique was used to assess rs۷۷۴۰۳۴۱۶۳ A>T polymorphism in ۹۱ paraffin blocks of stomach tissues (۴۲ GC patients and ۴۹ healthy subjects). Additionally, ۴۱ samples (۲۰ GC patients and ۲۱ healthy subjects) were selected randomly to assess DRD۱ gene expression using the qRT-PCR technique. Results: The ‘AT’ genotype of rs۷۷۴۰۳۴۱۶۳ was not significantly associated with GC (OR = ۰.۶۵, ۹۵% CI = ۰.۲۱۴-۱.۹۷۰, and p-value = ۰.۴۴۶); the ‘TT’ genotype was also not observed in our population. Regarding allele frequency, the ‘T’ allele is not correlated with GC (OR = ۰.۶۷۷, ۹۵% CI = ۰.۲۳۵-۱.۹۴۸, and p-value = ۰.۴۶۹). Furthermore, the expression of the DRD۱ gene in patients and healthy individuals demonstrated no noticeable difference (p-value = ۰.۸۳۵). Conclusions: According to the results, rs۷۷۴۰۳۴۱۶۳ A>T polymorphism is not associated with GC genotypically or allelically. Also, there is no correlation between increased gene expression levels of DRD۱ and the pathogenesis of GC.

Keywords:

Stomach Neoplasms , Receptors , Dopamine D۱ , Real-Time Polymerase Chain Reaction , Genetic Variation , Iran