Background: The extracellular matrix is a complex three-dimensional network of proteins and glycosaminoglycans, which have important roles in cellular physiology and cell-cell and cell-extracellular matrix interactions. Any changes in the extracellular matrix of tumors may be implicated in cellular transformation and metastasis. The aim of the present study was to identify changes in the hyaluronic acid of the stroma of colonic carcinoma.

Methods: Paraffin blocks of 30 patients with colon carcinoma (10 patients at each histological grade) were chosen from the pathology file of Khatam-Al-Anbia Hospital in Zahedan, Iran. Tissue sections (5-6 micrometers thick) were stained with hematoxylin-eosin and the alcian blue critical electrolyte concentration histochemical technique at pH=5.8. The intensity of the staining in each section was graded as 1, 2 or 3, referring to low, moderate or severe staining reactivities, respectively. Statistical data was analyzed with nonparametric tests by SPSS (ver. 10) and histopathological reports were prepared.

Results: The results of this study showed that there is a good correlation between histopathological grading and staining intensity of tumoral stroma for hyaluronic acid (p<0.005). Analysis using the Mann Whitney test revealed significant differences between staining grades 1 and 3 and grades 2 and 3 (p<0.005 and p<0.002, respectively), although there was no significant difference between staining grades 1 and 2 for hyaluronic acid.

Conclusions: The difference in staining intensity of the stroma in colon carcinoma is a result of different amounts of hyaluronic acid in stroma, indicating that increased levels of hyaluronic acid are associated with the invasion and metastasis of neoplastic cells.