Histochemical Analysis of Collagen Reorganization at the Tumor-Stromal Interface in Oral Squamous Cell Carcinoma- A Polarizing Microscopic Study

Stromal changes are the key factors for provision of nutrition and growth to any tumor and also they act as a barrier for spread of the tumor. There are limited histochemical studies in the literature on methods to detect, quantify and analyze the collagen in the invasive tumor front (ITF) of oral squamous cell carcinoma (OSCC). Aim: 1) To analyze the nature of collagen (thickness, hue, density, birefringence) with respect to cohesive and discohesive tumor front of oral squamous cell carcinoma. 2) To correlate the nature of collagen at the different grades (Broder's and Bryne's grading system) of oral squamous cell carcinoma. 3) Clinicopathological correlation with the nature of collagen at the invasive front of oral squamous cell carcinoma. Materials and Methods: Tissue sections of 30 OSCC cases with ITF were stained with hematoxylin and picrosirius red stains for evaluation of the nature of collagen under polarizing microscope. Results: Tumor with cohesive front will have thick collagen fiber which is predominantly organized red- yellow in color, well packed and shows strong birefringence (p< 0.005). A gradual change in the nature of collagen fiber was observed in the discohesive tumor front where the collagen fiber were thin disorganized, yellow-orange to green-yellow in color loosely packed with weak birefringence (p< 0.005). Conclusion: Cohesive tumor front with organized collagen fibers resist the tumor against invasion and metastasis, preventing it to increase in size and thus associated with initial stage of tumor (I&II) whereas in discohesive tumor front the fibers may enhance the movement of tumor cells towards invasion and metastasis.