Cyclooxygenase-2 overexpression in colorectal cancer is associated with non-polypoid growth.
BACKGROUND
Cyclooxygenase-2 is considered to play an important role in colorectal tumorigenesis. The purpose of this study was to clarify the relationship between cyclooxygenase-2 expression and morphology in colorectal cancer.


METHODS
We investigated cyclooxygenase-2 mRNA expression and type of growth (polypoid or non-polypoid according to Shimoda's classification) in 69 colorectal cancers by reverse transcription-polymerase chain reaction and histologic examination. Cyclooxygenase-2 mRNA expression was assessed as a ratio relative to cyclooxygenase-1 mRNA expression (cyclooxygenase-2 index).


RESULTS
Cyclooxygenase-2 indices in normal colorectal mucosa, polypoid cancer and non-polypoid cancer were 0.7 +/- 0.1, 1.0 +/- 0.1 and 1.9 +/- 0.1, respectively. The cyclooxygenase-2 index in non-polypoid cancer was significantly higher than in polypoid cancer (P = 0.0002) or normal mucosa (P < 0.0001). No difference in cyclooxygenase-2 index was found between polypoid cancer and normal mucosa (P = 0.67).


CONCLUSIONS
These results suggest that cyclooxygenase-2 overexpression in colorectal cancer is associated with non-polypoid growth.
Digestive Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Hidefumi
H
Tsunozaki
Keigo
K
Yoshinaga
Jirou
J
Kumagai
Kenichi
K
Sugihara
D000236:Adenoma / Q000201:enzymology / Q000473:pathology; D000368:Aged; D003111:Colonic Polyps / Q000201:enzymology / Q000473:pathology; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000473:pathology* / Q000601:surgery; D051546:Cyclooxygenase 2; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008207:Lymphatic Metastasis; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases