No abstract

Background: The purpose of the present study is to investigate the expression levels of STAT3, pSTAT3, MMP-7 and VEGF in colorectal adenocarcinoma, and also to determine association with the clinico-pathological parameters and co-expression of these genes. Methods: An immunohistochemical method was used to evaluate the expression of MMP-7 and VEGF genes in 93 archival tissues whereas STAT3 and pSTAT3 expression was determined in 75 cases. Results: Overexpression of STAT3 was detected in 26.7% (20/75), pSTAT3 in 13.4% (10/75), MMP-7 in 38.8% (36/93) and VEGF in 59.2% (55/93) of the colorectal carcinomas. STAT3, MMP-7 and VEGF immunopositivity were significantly correlated with poorly-differentiated tumors (P = 0.004; P = 0.03; P = 0.002, respectively) but not with other parameters. However, pSTAT3 immunostaining was not significantly associated with the clinico-pathological characteristics. Significant relationship was noted between overexpression of pSTAT3 and STAT3 (P < 0.001), pSTAT3 and VEGF (P = 0.044), pSTAT3 and MMP-7 (P = 0.003), and STAT3 and VEGF (P = 0.037) but marginal association was detected between STAT3 and MMP-7 (P = 0.057), and MMP-7 and VEGF (P = 0.052). Conclusion: Our data suggest that expression of these genes may have an important role in tumor dedifferentiation and may be useful as indicators of biologic aggressiveness. Co-expression of the bio-* Corresponding author. R. Naidu et al. 1176markers by cancer cells may have important implications in colorectal cancer biology and could be useful biological markers of the malignant phenotype.