Expression of carbonic anhydrase-IX in rectal cancer and its relationship with vascular endothelial growth factor and hepatic metastasis

Abstract

Objective To explore the differential expression of carbonic anhydrases-Ⅸ ( CA-Ⅸ )in 128 patients with rectal cancer,and study its association with vascular endothelial growth factor (VEGF)and hepatic metastasis of rectal cancer.Methods Western blotting was used to examine the expression of CA-Ⅸ and VEGF in different tissues of 128 patients with rectal cancer and 30 cases of normal rectal mucosa and rectal adenoma,and the influence of anthdrases's inhibitor ( acetazolamide ) on the rectal cancer cell growth was studied.Results The positive expression rate of both CA-Ⅸ and VEGF in carcinoma tissues of patients with hepatic metastasis was 83.3%,which was higher than that in normal rectal tissue ( 16.7%,0% ) and rectal adenoma ( 16.7%,36.7% ) and carcinoma tissues of patients without hepatic metastasis (72.1%,65.4% ,P ＜0.01 ).The expression of VEGF and CA-Ⅸ in mesorectal tissues of the patients with hepatic metastasis was not higher than that of the patients without hepatic metastasis.There was a negative association between the expression of CA-Ⅸ with VEGF and hepatic metastasis of the patients with rectal cancer.Acetazolamide obviously enhanced the chemotaxymotor ability of fluorouracil to increase the apoptosis of recetal cancer cells.Conclusion The CA-Ⅸ is highly expressed in rectal cancer tissues and can promote the growth and proliferation of rectal cancer cells,but it cann't be used as an independent index to make the diagnosis of hepatic metastasis in rectal cancer patients. Key words: Rectal cancer; Hepatic metastasis; Carbonic anhydrase-Ⅸ; Vascular endothelial growth factor