The expression of NMDA receptor I is associated with clinicopathological parameters and prognosis in the oral squamous cell carcinoma

BACKGROUND: Glutamate activates the N-methyl-D-aspartate (NMDA) receptors and this receptor is involved in the proliferation and migration of various tumour cells in vitro. However, the relationship between NMDA receptor expression and clinical parameters in cancer patients is unclear. Therefore, NMDA receptor 1 (NMDAR1) expression along with its clinical significance was examined in patients with oral squamous cell carcinoma (OSCC). METHODS: Eighty-one tumour specimens from OSCC patients were used to determine the NMDAR1 expression level by immunohistochemical staining. The control was obtained from a matched normal adjacent mucosa. The cases were considered to be positive if reactivity was displayed in >25% of the cells. RESULTS: The NMDAR1 reactivity was positive in 50 of 81 cases, while it was negative in the control. NMDAR1 expression was significantly associated with a lymph node metastasis (P = 0.008), the tumour size (P < 0.001), and the cancer stage (P = 0.034). The patients whose tumours expressed NMDAR1 had a significantly poorer survival than the patients who were NMDAR1-negative (log-rank = 6.45, d.f. = 1, P = 0.011). CONCLUSIONS: The NMDAR1 overexpression was significantly associated with the prognosis-related factors. Therefore, it might be one of the prognostic markers of OSCC.