Quantitative assessment of tumor-associated tissue eosinophilia and nuclear organizing region activity to validate the significance of the pattern of invasion in oral squamous cell carcinoma: A retrospective study

INTRODUCTION: Pattern of invasion (POI) in scoring system of oral squamous cell carcinoma (OSCC) can predict local recurrence and overall survival rate. Argyrophilic nucleolar organizer region (AGNOR) counts are considered to reflect the biosynthetic and nucleolar activity of a cell and thus serve as an indicator of the rapidity of the cell cycle thereby indicating the proliferative index of the tumor. It is implied that higher tumor associated tissue eosinophilia (TATE) showed lesser venous invasion, lymph node metastasis and clinical recurrence. The aim of the study was to assess and evaluate the following criteria's: POI-1 to POI-4 as defined by Bryne et al. in OSCC, proliferative index by AgNOR stain and TATE with carbol chromotrope stain in OSCC, validity of POI by correlating the AgNOR proliferative index and TATE. MATERIALS AND METHODS: Forty samples of formalin fixed paraffin embedded tissue blocks diagnosed of OSCC were taken for the study. Three sections were taken from a single block and then the tissues were stained differently with H & E Stain, AgNOR stain and Carbol chromotrope stain. First section stained with H & E was observed for POI and grading was done according to Bryne's criteria. The second and third sections were stained with AgNOR stain and Carbol chromotrope stain for proliferative index and TATE. One way analysis of variance was used to test the significance. RESULTS: Mean AgNORs count increases gradually from type 1 to type 4, depicting the increase in the nucleolar proliferative index of the cells and was statistically significant. In the case of the mean eosinophilic count, type 1 shows the highest mean eosinophilic count and the count shows drastic decrease till type 3 and from type 3 to type 4 the decrease is more gradual and was statistically significant. CONCLUSION: The study validated that POI is a good predictor for prognosis and also can be included in grading OSCC along with routine histopathological criteria.