Cyclooxygenase-2 expression and its relationship with proliferation of colorectal adenomas.
BACKGROUND
Cyclooxygenase (COX)-2 may be linked to carcinogenesis. In the previous study, we examined COX-2 expression immunohistochemically in 95 adenomas and reported a significant correlation between its expression and the grade of dysplasia. To clarify the correlation between COX-2 expression and cell proliferation, we investigated Ki-67 labeling index using immunohistochemistry and its correlation with COX-2 expression.


METHODS
Immunohistological staining for Ki-67 antigen was performed on 95 colorectal adenomas previously reported.


RESULTS
The Ki-67 labeling index was significantly higher in the high-COX-2 group than in the low-COX-2 and negative groups in adenomas with moderate (44.5 +/- 6.4% vs 33.0 +/- 2.6%, 39.0 +/- 6.2%; P = 0.01, P < 0.001, respectively) or severe dysplasia (47.2 +/- 7.6% vs 40.3 +/- 7.2%, 35.0 +/- 5.4%; P = 0.02, P = 0.005, respectively). There was no correlation between Ki-67 labeling index and COX-2 expression in mild dysplasia.


CONCLUSIONS
These results suggest that COX-2 may play a causal role in cell proliferation in carcinogenesis.
Sato
Takanobu
T
Digestive Surgery, Tokyo Medical and Dental University Graduate School, Tokyo, Japan. sato@po.kyoundo.jp
Yoshinaga
Keigo
K
Okabe
Satoshi
S
Okawa
Takuya
T
Higuchi
Tetsuro
T
Enomoto
Masayuki
M
Takizawa
Touichirou
T
Sugihara
Kenichi
K
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D000704:Analysis of Variance; D002455:Cell Division / Q000502:physiology; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D051546:Cyclooxygenase 2; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis* / Q000502:physiology; D019394:Ki-67 Antigen / Q000032:analysis; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000502:physiology
D007527:Isoenzymes; D019394:Ki-67 Antigen; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases