Histochemical analysis of collagen reorganization at the invasive front of oral squamous cell carcinoma tumors

Aim: The aim of the present study was to: (a) analyze the nature of collagen with respect to cohesive and discohesive invasive tumor front (ITF) of oral squamous cell carcinoma (OSCC); (b) analyze the clinicopathological correlation with the nature of collagen at the ITF of OSCC; and (c) correlate the nature of collagen with Broder's and Bryne's histological grading system of OSCC. Methods: Tissue sections of 29 OSCC with ITF were stained with hematoxylin-eosin and picrosirius red staining for evaluation under a polarized microscope. Results: Tumors with a cohesive front had a thick collagen fiber, are predominantly organized, red-yellow in color, well packed, and show strong birefringence (P<.005). A gradual change in the nature of the collagen fiber was observed in the discohesive tumor front, where the collagen fibers were thin, disorganized, yellow-orange to green-yellow in color, loosely packed, and with weak birefringence (P<.005). Conclusion: A cohesive tumor front with organized collagen fibers prevents tumor invasion and metastasis. As it is inhibits an increase in tumor size, it is associated with the initial stage of tumor (I & II), whereas in a discohesive tumor front, the fibers might enhance the movement of tumor cells, resulting in invasion and metastasis.