Immunoexpression of programmed cell death 4 protein in normal oral mucosa, oral epithelial dysplasia and oral squamous cell carcinoma.

Background: Oral squamous cell carcinoma (OSCC) is the frequently reported cancer of the head and neck. Recent studies are being conducted to evaluate the role of potential markers for diagnosing the stages of development of OSCC from normal cells.

Aim: The aim of this study is to evaluate and compare the immunoexpression of programmed cell death 4 (PDCD4) protein in normal oral mucosa, oral epithelial dysplasia (OED) and OSCC.

Materials and Methods: Histologically diagnosed, formalin-fixed paraffin-embedded archived cases ( n = 100) of normal mucosa ( n = 10), OED ( n = 60) and OSCC ( n = 30) were analyzed immunohistochemically in the present retrospective study using monoclonal rabbit antihuman PDCD4. OED and squamous cell carcinoma were graded according to the World Health Organization and Broder's histological grading criteria, respectively. Clinical parameters and immunohistochemical results were analyzed by Fisher exact test using SPSS software. P <0.05 was indicative of significant differences.

Results: PDCD4 expression was observed in the normal oral mucosa, OED and OSCC. The maximum expression was observed in the normal oral mucosa, which reduced significantly in OED and OSCC ( P = 0.017). With the increase in the transformation from normal cells to cancer cells, a shift from nuclear to cytoplasmic staining was observed indicating predominant cytoplasmic localization of stain as a feature of altered cells.

Conclusion: The present study delineates the molecular difference between the normal, dysplastic and carcinomatous cells; and points toward the role of PDCD4 localization in the proliferation of cells. This study thus highlights the need for further research with inclusion of long follow-up period and other pathological criteria such as inflammation and microenvironment, immune status of patient and tumor stage, which could aid in the development of prospective diagnostic options.