Expression of Mucin 4 in leukoplakia and oral squamous cell carcinoma: An immunohistochemical study

Mucins are large glycosylated proteins that act as a selective molecular barrier on the epithelial surface and engage themselves in morphogenetic signal transduction pathways. MUC4 (Mucin 4) is a transmembrane mucin, that protects and lubricates the mucous membranes of the human body and involves itself in various cellular functions like growth, differentiation and signaling. An aberrant expression of MUC4 has been demonstrated in various human cancers. A thorough literature survey shows very few studies about MUC4 expression in normal and cancerous oral mucosa.

Our study aimed at investigating the expression pattern of MUC4 in normal oral mucosa, oral leukoplakia and oral squamous cell carcinoma (OSCC) in an attempt to analyze its role played in oral carcinogenesis.

Formalin-fixed paraffin-embedded tissues of five cases of normal tissue, 15 cases of leukoplakia, 10 cases of well-differentiated squamous cell carcinoma and 10 cases of moderately differentiated squamous cell carcinoma were retrieved from the archives of the department and MUC4 antigen was immunohistochemically localized.

The result was subjected to statistical analysis using Pearson's Chi-square test and an intergroup analysis was performed using one-way analysis of (ANOVA).

A total of 46.7% of leukoplakia and 70% of OSCC were stained positive with MUC4 antigen. Maximum intensity of staining was noted in well-differentiated OSCC. A steady increase in MUC4 staining was noted from normal oral tissues to leukoplakia to OSCC.

The findings of the study suggest that MUC 4 plays a vital role in the pathogenesis of OSCC and can be regarded as a useful marker for oral dysplasia and OSCC.