Objective:To observe the expressions of 11beta-hydroxysteroid dehydrogenase types 1 and 2 in colorectal cancer. Methods:Neoplastic tissues and autologous non-neoplastic tissues were taken from 12 patients with colorectal cancer immediately after the operations. The mRNA expressions of 11beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and 11beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2) were detected by reverse transcription polymerase chain reaction (RT-PCR). The protein expressions of 11β-HSD1 and 11β-HSD2 were detected by Western-blot assay. Results:Both isoforms of 11β-HSD expressed in the colon adenocarcinoma, but their expressions were not identical in neoplastic and non-neoplastic tissues. There was a significant decrease of 11β-HSD2 mRNA abundance and protein abundance in neoplastic tissue. 11β-HSD1 protein and mRNA abundance were not signiifcantly different from that in control tissue. Conclusions:Neoplastic transformation is associated with the decreases of 11β-HSD2 mRNA and protein.