Dopamine receptor gene (DRD1-DRD5) expression changes as stress factors associated with breast cancer.

Breast cancer is the most common cancer among females worldwide and a most prevalent malignancy in Iranian women. Chronic stress may make an important contribution to cancer, especially in the breast. Numerous studies showed roles of neurotransmitters in the occurrence and progression of cancers which are mediated by their various types of receptors. This study was conducted to evaluate alterations in the expression profile of dopamine receptor genes in peripheral blood mononuclear cells (PBMC) as stress factors in breast cancer patients and the human breast cancer cell line (MCF-7). Peripheral blood samples were obtained from 30 patients and 30 healthy individuals. Total mRNA was extracted from PBMC and MCF-7 cells and RT-PCR was performed to confirm the presence of five dopamine receptors (DRD1-DRD5). Expression changes of dopamine receptor genes were evaluated by real time PCR. We observed that DRD2-DRD4 in PBMCs of breast cancer patients were increased compared to healthy individuals. In addition, all dopamine receptor subtypes but DRD1 were expressed in MCF-7 cells. Therefore, alterations of these receptors as stress factorsshould be assessed for selecting appropriate drugs such as D2-like agonists for treatment of breast cancer after performing complimentary tests. Determining the expression profile of dopamine receptor genes thus seems promising.