Immunohistochemical evaluation of Ki-67 and Nucleostemin in a model of oral potentially malignant disorders to malignant lesions

Background Proliferative biomarkers are one among the tumor markers that assist in tailored clinical management, thus could aid in improving the quality of life of patients with head and neck cancers. The present study aims to explore the clinical significance and relevance of Nucleostemin (NS) as a proliferative marker along with Ki-67, a known diagnostic proliferative marker in oral potentially malignant disorders (OPMD) and oral squamous cell carcinoma (OSCC), by evaluating the immune expression of these biomarkers. Methods A retrospective immunohistochemical (IHC) analysis of NS & Ki-67 was performed on a total of 90 primary cases, i.e., leucoplakia with dysplasia (LWD, n = 15), oral submucous fibrosis (OSMF, n = 15), OSCC (n = 60), correlated with clinicopathological features. Results An overexpression of these markers was observed in the upper strata of the epithelium of histologically diagnosed severe dysplasia, moderately advanced OSMF (among the OPMD) and similar expression was seen in moderately and poorly differentiated carcinoma. The clinicopathological features did exhibit a significant correlation in advanced stage of the disease. Normal oral mucosa, adjacent to the lesion showed NS expression only in the basal strata with few cells in the lower spinous layer. Among OPMD, dysplasia (n = 5) and advanced OSMF (n = 2) exhibiting increased expression, progressed to malignancy. Conclusions The presence of NS and Ki-67 in various strata of the diseased mucosa was able to identify a few cases in OPMD with a cut-off value of 31.9 for NS and 23.9 for Ki-67 progressing into OSCC. However, this method is challenging for routine diagnosis.