Evaluation of stromal myofibroblasts in oral leukoplakia, oral submucous fibrosis, and oral squamous cell carcinoma--an immunohistochemical study.

Abstract

Oral leukoplakia (OL) and oral submucous fibrosis (OSMF) are the main potentially malignant disorders and oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral mucosa. Myofibroblasts (MFs) secrete numerous growth factors and inflammatory mediators that stimulate epithelial cell proliferation and play an important role in tumoral invasion and use a combination of different factors in the course of neoplastic growth and development. Hence the present study was undertaken to evaluate and compare the distribution of MFs using alpha smooth muscle actin (α-SMA) in OL, OSMF, and various histopathological grades OSCC. Sixty formalin-fixed paraffin-embedded tissue blocks consisting of histopathologically diagnosed cases of normal mucosa (n = 10), OL (n = 14) hyperkeratosis with various grades of dysplasia, OSMF (n = 11), and OSCC (n = 25) were subjected to immunohistochemistry using α-SMA antibody for detection of MFs. MFs were not detected in normal oral mucosa. On comparison of frequency of mean scores in OL, OSMF, and OSCC the values were 0.6 ± 0.2 (0-2), 1.2 ± 0.68 (1-2), and 2.6 ± 1.34 (0-4), respectively. The results were statistically significant (P < 0.001). These findings are suggestive of role of MFs with the creation of a permissive environment for tumor invasion in OSCC. Hence the presence of MF is a prognostic marker and evaluation of the frequency in the stroma can be used as therapeutic targets.