Background and Objectives:To determine the immunohistochemical (IHC) localization of basement membrane component laminin in histological grades of oral squamous cell carcinoma (OSCC). The purpose of this study was to demonstrate the loss of continuity of the basement membrane in OSCC using an antibody directed against laminin using advanced polymer staining system.Materials and Methods:A total of 30 cases of OSCC: 10 cases of well differentiated squamous cell carcinom (WDSCC), 10 cases of moderately differentiated squamous cell carcinoma (MDSCC), and 10 cases of poorly differentiated squamous cell carcinoma (PDSCC) were subjected to heat-induced antigen retrieval method using ethylene-di-amine-tetraacetic acid buffer in a microwave oven. Then the sections were stained with anti-laminin polyclonal antibody and visualized using super sensitive polymer horseradish peroxidase detection system. In each case, the integrity of the basement membrane laminin was assessed by using statistical analysis.Results:Statistical analysis showed a decreased distribution of laminin from WDSCC to MDSCC to PDSCC (P value 0.0573). The intracytoplasmic staining of laminin gradually increased from WDSCC to MDSCC to PDSCC (P value 0.0198).Interpretation and Conclusion:WDSCC cases showed more laminin expression in basement membrane around the tumor islands and less loss of continuity compared to MDSCC and PDSCC cases suggesting a greater enzymatic degradation of basement membrane components in MDSCC and PDSCC than WDSCC. The loss of structural basement membrane laminin and the presence of laminin in the tumor cells of PDSCC cases suggest that laminin helps in tumor invasion. The expression of laminin in the basement membrane may be a useful parameter to evaluate tumor histologic differentiation and aggressiveness.

Dr. Albert Coons et al in 1941 first initiated immunohistochemistry to identify cellular or tissue constituents by means of antigen and antibody interactions. The site of antibody binding can be identified either by direct labeling of antibody or by use of secondary labeling method. Immunohistochemistry (IHC) involves the use of labeled antibodies to localize the antigens in the tissues through antigen-antibody interactions and are visualized either by fluorescent dye, enzyme, radioactive element or colloidal gold. IHC usage has an obvious advantage over the traditional one, which uses special enzyme staining technique that identify only limited number of proteins, enzymes and certain tissue structure. IHC can be commonly employed to distinguish the tissue of epithelial and mesenchymal differentiation, cellular changes which are normally not visible in regular staining techniques, and earliest changes in transformed tissues. IHC is relatively rapid and simple method to better determine the specific neoplastic tissue origin, the behavior or progression of neoplasm. Hence IHC have gained importance in the medical research and has been considered as a crucial & widely used technique in research laboratories as well as in clinical diagnostics. In present review IHC markers for epithelial origin that can be utilized to diagnose the tumor or to determine the prognosis of the tumor..