AIM: To study CD34, CD105, inducible nitric oxide synthase (iNOS), endogenous nitric oxide synthase (eNOS), and hypoxia-inducible factor 1 (HIF-1) α expression in human colorectal carcinomas.

METHODS: The tissue microarrays (TMAs) were made up of 80 cases of colorectal carcinoma and 80 cases of non-neoplasm colorectal mucosa. The expression of CD34, CD105, NOS and HIF-1α was detected by immunohistochemistry (SP).

RESULTS: iNOS and HIF-1α expression in colorectal carcinoma was significantly higher than in non-neoplasm colorectal mucosa (χ 2= 43.166, P< 0.01; χ 2= 10.4278, P< 0.01); eNOS expression in colorectal carcinoma was significantly lower than in non-neoplasm colorectal mucosa (χ 2= 11.354, P< 0.01). The expression of iNOS correlated with differentiation (χ 2= 18.141, P< 0.01), invasive depth (χ 2= 4.748, P< 0.01), and Micro vessel density (MVD)(t= 2.327, P< 0.05). The expression of HIF-1α was correlated with infiltrating depth (χ 2= 4.397, P< 0.05), Duke’s staging (χ 2= 4.255, P< 0.05), and MVD (t= 2.272, P< 0.05). No correlation was found in eNOS expression.

CONCLUSION: Over-expression of iNOS and HIF-1α in colorectal carcinoma is correlated with the biological character MVD.