CD44 Expression in Oral Lichen Planus and Related Lesions-An Immunohistochemical Study

Cluster of differentiation 44 (CD44) is a cell surface adhesion protein involved in the progression and metastasis of oral squamous cell carcinoma. The current study aims to evaluate the expression of CD44 in oral lichen planus and related lesions and thereby assess the relative risk of malignant transformation of these lesions.

Formalin-fixed paraffin-embedded tissue blocks of 10 oral lichen planus (Group 1), 10 oral lichenoid lesions (Group 2), 8 with oral lichen planus with dysplasia (Group 3), and 5 with lichenoid dysplasia (Group 4) were included in the study. Immunostaining was done for the tissue sections using CD44 mouse monoclonal antibody. Staining density, staining intensity, and immunoreactive scores of CD44 were evaluated in all four groups. Statistical analysis was done by Statistical Package for the Social Sciences® software and the Kruskal-Wallis test was used.

CD44 staining pattern of lichenoid dysplasia and lichen planus with dysplasia changed from membranous to cytoplasmic. The membranous CD44 immunoreactivity was mild with a score of 2.25 for Group 3 and 1.6 for Group 4 whereas moderate for other groups with a P-value of 0.009. The cytoplasmic immunoreactivity was significantly high in Group 3 (5.3 ± 2.6) followed by Group 4 (3.2 ± 1.2), Group 2 (1 ± 1.8), and Group 1 (0.7 ± 1.3) with a P-value of 0.001.

The CD44 membranous immunoreactivity scores were low while the cytoplasmic immunoreactivity was high in oral lichen planus with dysplasia and oral lichenoid dysplasia when compared to oral lichen planus and oral lichenoid lesions. CD44 immunostaining pattern can help in assessing the malignant transformation of oral lichen planus or lichenoid lesions.