Malignant Parotid Gland Tumors Biomarkers Panel for the Noninvasive Detection of Benign and Discovery and Prevalidation of Salivary Extracellular microRNA

Purpose: This study was conducted to explore the differences in salivary microRNA (miRNA) profiles between patients withmalignant or benign parotid gland tumors as a potential preoperative diagnostic tool of tumors in the salivary glands. Experimental Design:Whole saliva samples from patients with malignant (n1⁄4 38) or benign (n1⁄4 29) parotid gland tumors were obtained from the Salivary Gland Tumor Biorepository (SGTB). After total RNA isolation, human miRNA cards were used for miRNA profiling. The differential miRNA expression was analyzedusing two-sidedWilcoxon test.Quantitative real-timePCR (qRT-PCR)wasused to validate selected miRNAs in an independent sample set. Receiver-operating characteristics curve and probability of malignancy was exploited to evaluate the diagnostic power of the validated miRNAs. Results: With miRNA profiling, 57 of 750 investigated miRNAs were differently expressed, of which 54 showedhighermiRNA expression in samples frompatients withmalignant tumors than those frompatients with benign tumors. Validating the expression in an independent sample set of 9 miRNAs revealed indeed higher expression of miRNAs in malignant samples compared with benign samples. The expression of 6 validated miRNAs was statistically significantly different between the two groups (P < 0.05). A four miRNA combination was able to discriminate between saliva samples from patients with malignant tumors from those of patients with benign parotid gland tumors (sensitivity 69%, specificity 95%). Conclusions: Salivary miRNA profiles differ in saliva from patients with malignant from saliva from patientswith abenignparotid gland tumor. Thesepreliminary results arepromising todevelopanoninvasive diagnostic tool for diagnosing tumors in the salivary glands.Clin Cancer Res; 19(11); 3032–8. 2013 AACR.