The Significance of Carbonic Anhydrase Expression in Human Colorectal Cancer

Gastroenterology. 1993 Sep;105(3):820-6. doi: 10.1016/0016-5085(93)90900-w.


Background: Carbonic anhydrase isoenzymes I and II are present in normal colorectal mucosa. This study aimed to determine if carbonic anhydrase is present in colorectal cancer and what is its potential clinical significance.

Methods: The messenger RNA (mRNA) and protein expression of carbonic anhydrase isoenzyme I were analyzed in fresh specimens of colorectal adenocarcinoma by Northern and Western blots, respectively. The immunohistochemical expression was subsequently studied in a larger number of formalin-fixed surgical specimens.

Results: All of 30 normal colon samples had a strong RNA hybridization signal. Only 4 of 39 paired colorectal cancer and none of 9 normal liver samples had detectable levels of carbonic anhydrase mRNA. Isoenzyme I protein expression showed similar results. In a separate group of patients, immunohistochemical studies showed that 16 of 96 colorectal tumors had positive staining cells. All positive tumors were well or moderately differentiated carcinomas (P < 0.05). When analyzed retrospectively, immunoreactive cases were more likely to be in a group with a good outcome (P < 0.01) and to lack vascular invasion (P < 0.01) than negative cases.

Conclusions: The majority of colorectal cancers do not express carbonic anhydrase isoenzyme I. The presence of any isoenzyme I-positive immunoreactive cancer cells may be associated with a more favorable outcome in colorectal cancer.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Blotting, Northern
  • Blotting, Western
  • Carbonic Anhydrases / analysis*
  • Carbonic Anhydrases / genetics
  • Colonic Neoplasms / enzymology*
  • Colonic Neoplasms / epidemiology
  • Colonic Neoplasms / pathology
  • Colorectal Neoplasms / enzymology
  • Female
  • Gene Expression Regulation, Neoplastic / genetics
  • Humans
  • Immunohistochemistry
  • Intestinal Mucosa / enzymology
  • Intestinal Mucosa / pathology
  • Isoenzymes / analysis*
  • Isoenzymes / genetics
  • Male
  • Middle Aged
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Retrospective Studies
  • Tumor Cells, Cultured


  • Isoenzymes
  • RNA, Messenger
  • Carbonic Anhydrases