Dopamine receptor D2 is correlated with gastric cancer prognosis.

It has been reported previously that a dopamine receptor D2 (DRD2) antagonist was able to induce cancer cell apoptosis and that DRD2 was expressed at high levels in pituitary adenomas. However, the expression of DRD2 in gastric cancer and its correlation with the prognosis of patients with gastric cancer remain to be elucidated. In the present study, the expression of DRD2 in 84 paired gastric cancer tissues and respective adjacent non-cancerous tissues were detected using an immunohistochemical assay. The correlation between the expression of DRD2 and the with survival durations of the patients with gastric cancer was analyzed using Kaplan-Meier analysis. In addition, online resources were utilized to further analyze the correlation between the mRNA expression level of DRD2 and prognosis. The effect of the DRD2 antagonist, thioridazine, on the proliferation of the AGS gastric cancer cells was determined. The results of the present study showed that the percentage of gastric cancer cases with a high expression level of DRD2 (51.2%) was higher, compared with that of cases with a low expression level of DRD2 (39.3%). Patients with a higher expression of DRD2 had shorter survival durations. The online database analysis revealed that the expression of DRD2 was also inversely correlated with the prognosis of patients with gastric cancer. Furthermore, the DRD2 antagonist, thioridazine, inhibited the growth of AGS gastric cancer cells. In conclusion, as the expression of DRD2 was negatively correlated with survival durations in patients with gastric cancer, it may be considered as a prognosis marker in the future. Developing DRD2 antagonists may assist in increasing the efficiency of cancer therapy.