Expression of cluster differentiation-44 stem cell marker in grades of oral epithelial dysplasia: A preliminary study

Oral cancer is one among the alarming diseases related to oral cavity. Its prevalence and incidence have increased in many folds, in the past decade. This has led the investigators to find the preliminary stages and related early evaluating methods to restrain it. Few clinical lesions such as leukoplakia, erythroplakia, oral submucous fibrosis and lichen planus reflected malignant changes. These premalignant disorders provided scope to assess the underlying cellular and molecular events, which shall be helpful in early detection, aggressiveness and prognosis of the patient.

Forty formalin fixed, paraffin embedded blocks were utilized and evenly subdivided into Group I - control tissue, Group II - mild epithelial dysplasia, Group III - moderate epithelial dysplasia and Group IV - severe epithelial dysplasia. The study group was categorized based on the WHO classification of dysplasia 2005. Routine staining was performed to reconfirm the diagnosis of all the samples. Simultaneously, immunohistochemical staining was done with cluster differentiation-44 (CD44) antibody. Positive cells were counted on 10 representative fields with a minimum of 100 cells per field using ×20.

Comparison of four groups with respective to number of positive cells was done using Kruskal-Wallis ANOVA test. Pair-wise comparison of three grades of oral epithelial dysplasia and the controls was done using Mann-Whitney U test.

The mean of Group I is 745.50, Group II is 665.20, Group III is 530.10 and Group IV is 322.90. A statistically significant P = 0.00001 was ascertained on comparison of the mean between the groups.

CD44, a cell membrane marker could help in cell adhesion and cell-cell interactions. Loss of CD44 expression enhances the binding of the growth factors with their principle receptors that enhances the cellular proliferation. It can be used as a prognostic marker for identifying the rate of malignant transformation in these disorders.