Serum IRS-1 acts as a novel biomarker for diagnosis in patients with nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a major head and neck cancer with high occurrence in Southeast Asia and southern China. Insulin receptor substrate 1 (IRS-1) plays an important role in the development, progression, invasion and metastasis of tumors. The purpose of this study was to evaluate whether IRS-1 could be used as biomarkers for the diagnosis of NPC through measuring their expression and assess their relationship with clinical pathological factors. METHODS: Quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot were used to analyze the expression of IRS-1 in 133 NPC patients and 104 healthy controls. The relationship between IRS-1 expression and clinicopathological characteristics in NPC was estimated through chi-square test. We calculated diagnostic values of serum IRS-1 expression by receiver operating characteristic (ROC) curve. RESULTS: This study reports that IRS-1 protein was weakly expressed in NPC specimens, but highly in healthy controls. Serum IRS-1 were up-regulation in NPC patients compared with healthy controls. Their up-regulation was significantly correlated with lymph node status (P=0.029). Furthermore, the value of the area under the receiver-operating characteristic curve (AUC-ROC) was 0.907. The optimal cutoff value was 2.255, providing a sensitivity of 88.0% and a specificity of 77.9% in differentiating NPC patients from healthy controls. CONCLUSION: Our data indicates that serum IRS-1 might increase the sensitivity and accuracy in diagnosis of NPC, and may be a potential target for diagnosis and gene therapy.