Evaluation of DRD1 Gene Expression Pattern and rs774034163 Genetic Polymorphism in Patients with Gastric Cancer: A Case-Control Study in Iran

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 D1 (DRD1) 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 DRD1 (rs774034163 A>T) among Iranian patients suffering from GC in Isfahan.

ARMS PCR technique was used to assess rs774034163 A>T polymorphism in 91 paraffin blocks of stomach tissues (42 GC patients and 49 healthy subjects). Additionally, 41 samples (20 GC patients and 21 healthy subjects) were selected randomly to assess DRD1 gene expression using the qRT-PCR technique.

The ‘AT’ genotype of rs774034163 was not significantly associated with GC (OR = 0.65, 95% CI = 0.214-1.970, and p-value = 0.446); the ‘TT’ genotype was also not observed in our population. Regarding allele frequency, the ‘T’ allele is not correlated with GC (OR = 0.677, 95% CI = 0.235-1.948, and p-value = 0.469). Furthermore, the expression of the DRD1 gene in patients and healthy individuals demonstrated no noticeable difference (p-value = 0.835).

According to the results, rs774034163 A>T polymorphism is not associated with GC genotypically or allelically. Also, there is no correlation between increased gene expression levels of DRD1 and the pathogenesis of GC.