Comparison of expression of myofibroblasts in normal oral mucosa, oral epithelial dysplasia, and oral squamous cell carcinoma using α-SMA and vimentin: An immunohistochemical study

Role of myofibroblasts in oral plasma cell granuloma: Immunohistochemical evaluation of α-SMA and ALK in a retrospective study of 30 cases

INTRODUCTION

Oral plasma cell granuloma (OPCG) is a rare reactive lesion with generally benign yet occasionally aggressive behavior. Myofibroblasts are important in many physiologic, and pathologic conditions. The role of myofibroblasts in the clinical behavior of OPCG was assessed as well as its usefulness in differentiating this lesion from the inflammatory myofibroblastic tumor mimicking plasma cell granuloma.

MATERIAL AND METHODS

This retrospective study included 30 paraffin blocks of OPCG. Immunohistochemical evaluation of alpha-smooth muscle actin (α-SMA) and Anaplastic lymphoma kinase (ALK) antibodies was performed. The mean area of positive expression was calculated and scored semiquantitatively with clinicopathologic correlations.

RESULTS

Most of the cases were clinically non-aggressive. Alveolar bone resorption was observed in nine cases, two of them showed severe resorption and stromal fibrosis. Negative α-SMA was observed in 70% of cases showing a predominance of plasma cells in the stroma. All cases of stromal fibrosis revealed positive α-SMA of a weak percentage. A statistically significant difference was observed between α-SMA expression and the clinicopathologic variables. Negative ALK expression was noted in all cases.

DISCUSSION

Myofibroblasts were infrequently found in OPCG. Remarkably, the aggressive behavior in cases with intense fibrosis was related to the existence of myofibroblasts even of non-neoplastic nature and minimal amount. The number of myofibroblasts and their nature assessed via α-SMA and ALK immunohistochemical expression respectively might be valuable in predicting the biological behavior of OPCG and may hold diagnostic significance in challenging OPCG cases that might mimic inflammatory myofibroblastic tumor.

Establishment of the role of myofibroblasts in invasive process of oral squamous cell carcinoma: A pilot study

Aims

To establish the role of myofibroblasts in invasive process of oral squamous cell carcinoma (OSCC).

Materials and Methods

Four study groups were formed as follows: group 1 consisting of 30 cases of well-differentiated OSCC, group 2 consisting of 30 cases of moderately differentiated OSCC, group 3 consisting of 30 cases of poorly differentiated OSCC, and group 4 consisting of controls. Staining of all of the specimens was done using a-SMA antibody through immunohistochemistry (IHC) procedure. Multiplication product of staining intensity (A) and percentage of a-SMA-stained immuno-positive cells (B) gave a final staining index (FSI). According to FSI, score zero was graded as index zero; score one and two were graded as index low; score three and score were graded as index moderate; and score six, seven, eight and nine were graded as index high.

Results

Mean FSI among specimens of groups 1, 2, 3, and 4 was 7.93, 8.47, 8.8, and 0, respectively. Non-significant results were obtained while comparing the mean final staining index among specimens of groups 1, 2 and 3. However; while comparing between groups 1 and 4, groups 2 and 4, and groups 3 and 4, significant results were obtained. While comparing the FSI among overall OSCC group (groups 1, 2 and 3) and controls (group 4), significant results were obtained.

Conclusion

Myofibroblasts are an integral component of processes associated with the creation of a permissive environment for cancer invasion process in patients with OSCC.

Clinical Significance

Myofibroblasts are associated with the creation of progressive and invasive processes of oral squamous cell carcinoma. Hence, they might be employed as a part of future target for therapeutics in cancer therapy.

Immunohistochemical evaluation of myofibroblasts in oral epithelial dysplasia and oral squamous cell carcinoma

Aim:

The aim of the study is to evaluate the presence of myofibroblasts quantitatively in oral epithelial dysplasia, oral squamous cell carcinoma (OSCC).

Materials and Methods:

Formalin-fixed, paraffin-embedded blocks were retrieved from the institutional archives. The sample size is 35 and included 15 cases of oral epithelial dysplasia (n = 15), 15 cases of squamous cell carcinoma (n = 15) and 5 cases of normal oral mucosa which served as the control (n = 5). Histologic sections were subjected to immunohistochemical analysis using alpha-smooth muscle actin, and the mean number of myofibroblasts was evaluated.

Results:

There were no myofibroblasts in the stroma of normal oral mucosa and oral epithelial dysplasia. Whereas all cases of OSCC showed myofibroblasts (mean ± standard deviation: 21.49 ± 9.76). This difference of myofibroblasts between OSCC and oral epithelial dysplasia was statistically significant with a P < 0.05. There was no statistically significant difference in the mean number of Myofibroblasts(MF) between 3 histologic grades of OSCC.

Conclusion:

The presence of myofibroblasts in the stroma of OSCC and their absence in normal oral mucosa and epithelial dysplasia reveals that these cells may play a role in cancer cell invasion and progression so the treatment strategies targeting the myofibroblasts and their by products may be beneficial in OSCC patients.