Characterization, Localization and Patterning of Lymphatics and Blood Vessels in Oral Squamous Cell Carcinoma: A Comparative Study Using D2-40 and CD-34 IHC Marker.

Abstract

Lymphatic metastasis has always been regarded as a major prognostic indicator for disease progression and as a guide for therapeutic strategies to oral squamous cell carcinoma (OSCC). Differentiating lymphatic vessels from blood vessels is difficult, partly due to lack of specific method for identifying lymphatics. A new lymphatic vessel reactive antibody D2-40 has been introduced recently. Here we examined immunohistochemical localization of lymphatic vessels and blood vessels using D2-40 and CD-34 respectively in different histological grades of OSCC. Their expression in intra-tumoural and peri-tumoural region was also compared. Forty two formalin-fixed paraffin-embedded tissue blocks of excised specimens of OSCC were immunohistochemically evaluated using D2-40 and CD-34 antibodies. Lymphatic vessel density (LVD) (D2-40 positivity) and micro vessel density (MVD) (CD34 positivity) in both intratumoural and peritumoural areas were assessed by hot spot method. Regardless of histopathological differentiation, LVD-- and MVD in peritumoural areas were found greater than intratumoural areas (p>0.05). Interestingly, other than lymphatic vessels, D2-40 positivity was also detected in tumour cells as well as in basal layer of epithelium adjacent to OSCC. Two patterns of distribution of CD34 positive vessel - circumscribing type and penetrating type were also observed in the cancer nest area. D2-40 can be used as a marker to differentiate lymphatic vessels from blood vessels. Lymphatic and blood vessel proliferation might be much more extensive in the peritumoural area. D2-40 expression in epithelium adjacent to tumour indicates its role in the process of differentiation. Further, its expression in potential malignant disorder may provide better insight in predicting prognosis and pathogenesis of these lesions.