Immunohistochemical Characterization of Bcl-2 in Oral Potentially Malignant Disorders

Bcl-2 is a group of apoptotic proteins that play a key role in cellular homeostasis. Overexpression of Bcl-2 has been associated with the poor prognosis of oral squamous cell carcinoma (OSCC). The aim of this study is to analyze the immunohistochemical expression of Bcl-2 in healthy oral mucosa, different oral potentially malignant disorders and OSCC, and to determine its diagnostic value. A retrospective observational study was carried out in the Oral Medicine Unit of the University of Santiago de Compostela. All the clinicopathologic data were collected and paraffin-embedded blocks were available to perform the immunohistochemistry study with Bcl-2. We studied 18 fibromas, 15 OSCC, 29 oral leukoplakia lesions (OL), 59 oral lichen planus (OLP) cases, and 16 healthy controls. OL with epithelial dysplasia (31.2%) showed the highest expression of Bcl-2 and OLP (1.9%) showed the lowest expression of Bcl-2 (P=0.025). Receiver operating characteristics curves showed that the detection of Bcl-2 enables discrimination between OL and OLPs (sensitivity: 58.6%, specificity of 99.32%). Bcl-2 negative expression in the OLP diagnosis obtained an odds ratio of 13.750 (95% confidence interval: 3.354-56.369; P<0.0001) and the positive expression in the OL 4.468 (95% confidence interval: 1.889-10.565; P=0.001). Bcl-2 could be used as a diagnostic biomarker to study their malignant transformation.