Expression and clinical significance of carbonic anhydrase 1 in different clinical stages of colorectal cancers

Abstract

Objective To investigate the expression pattern of carbonic anhydrase 1 (CA1) in different clinical stages of color ectal cancers and the correlation between CA1 expression and pathologic characteristics of colorectal cancer.Methods The expression of CA1 in genetic level was detected by real-time quantitative polymerase chain reaction (PCR) and the expression of CA1 in protein level was detected by Western blot and immunohistochemical staining.Results The expression pattern of CA1 in the protein level was very similar to the genetic level.It had a very low expression level in carcinoma tissue,especially at stages Ⅲ and Ⅳ (P ＜0.01),CA1 had significantly lower expression level in the colorectal patients with metastasis (P ＜0.01).CA1 was gradually decreased from well-differentiation tissue to poorly-differentiation tissue with a significant difference between well-differentiated adenocarcinoma and poorly-differentiated adenocarcinoma (P ＜ 0.01).Kaplan-Meier survival analysis showed that the expression of CA1 was extremely related to colorectal carcinoma (CRC) prognosis.The 5-year survival rate was only 8％ in the CA1 negative expression group,and the 5-year survival rate of the patients with CA1 positive expression was 92.86％ (P ＜ 0.01).Conclusions CA1 had the similar expression patterns at genetic and protein levels.In the colorectal cancer tissue,the expression of CA1 was downregulated and even missing.CA1 had significantly lower expression level in the advanced colorectal cancers with metastasis and poorly differentiated colorectal cancer tissues.The patients with lower CA1 expression level had the worse prognosis. Key words: Carbonic anhydrases/genetics ; Gene expression; Colorectal neoplasms/pathology; Colorectal neoplasms/genetics; Blotting, Western; Immunohistochemistry; Neoplasm staging; Neoplasm metastasis