Diagnostic accuracy of human transcriptional activator (Myb) expression by ELISA technique versus immunohistochemistry in detecting salivary gland carcinomas

Abstract

Aim: To assess the expression of Myb in the saliva and salivary gland tissues of patients suffering from salivary gland tumors to find out its ability to differentiate between salivary gland carcinomas and benign tumors. Materials and Methods: This was a prospective study comprising 70 patients with salivary gland tumors classified into two equal groups: 35 patients had benign tumors and 35 patients had malignant salivary gland carcinomas. Expression of Myb level in the saliva and salivary gland tissues of the patients was measured by enzyme-linked immunosorbent assay (ELISA) and detected by immunohistochemical (IHC) analysis. For parametric data, Student’s t test was used, and for nonparametric data Mann–Whitney U test was used. However, qualitative data were presented as frequencies and percentages. Chi-square test or Fisher’s exact test, when applicable, was used for the comparisons. ROC (receiver-operating characteristic) curve was constructed to determine the cutoff values of Myb for differentiation between the groups. Results: There was a statistically significant difference (P = 0.029) of Myb level in saliva and tissue in the malignant group in comparison to the benign group. Myb ELISA test in salivary gland tissues at a cutoff value of 355 mg/g could discriminate between benign and malignant salivary gland tumors with an 88.9% sensitivity, 86.7% specificity, and accuracy amounting to 91.8%. At a cutoff value of 78.9 mg/mL, Myb ELISA test in saliva could discriminate between benign and malignant salivary gland tumors with an 85.6% sensitivity, 79.7% specificity, and accuracy amounting to 83.4%. In tissues, Myb detection by IHC is significantly more diagnostic than by ELISA. Conclusion: Myb expression by ELISA was markedly observed in salivary gland tumors especially malignant carcinoma. Therefore, it can be used as a simple primary marker for the detection of salivary gland tumors in saliva or tissue biopsy. Myb expression evaluation by ELISA can differentiate between malignant and benign salivary gland tumors. The level of Myb detected in saliva can furnish an early diagnosis of salivary gland cancer as well as a noninvasive aid to monitor recurrence of malignant salivary gland lesions.