Expression of cyclooxygenase-2 and its relationship to p53 accumulation in colorectal cancers.
OBJECTIVE
Cyclooxygenase (COX)-2 is an inducible isoform responsive to cytokines, mitogens, and growth factors, and is believed to be an important enzyme related to colorectal cancer (CRC). Existing evidence suggests that COX-2 expression is normally suppressed by wild-type p53 but not mutant p53, suggesting that loss of p53 function may result in the induction of COX-2 expression. The aim of this study was to determine the relationship between COX-2 expression and p53 levels in CRC.


METHODS
Patients with sporadic colorectal adenocarcinoma (n=161) who underwent curative surgery in Chosun University Hospital were enrolled in this study. Expression of COX-2 and p53 proteins was examined by immunohistochemistry in paraffin-embedded cancer tissue blocks, and the relationship between COX-2 and/or p53 expression with clinicopathologic parameters was analyzed.


RESULTS
Expression of COX- 2 was positive in 47.8% of colorectal cancers, and significantly associated with the depth of tumor invasion (p= 0.042). In contrast, p53 was positive in 50.3% of the cases, and was associated with both age (p=0.025) and the depth of tumor invasion (p=0.014). There was no correlation between COX-2 expression and p53 expression (p=0.118).


CONCLUSIONS
These results suggest that COX-2 expression might play an important role in the progression of colorectal cancer. However, COX-2 expression was not associated with mutational p53. Further studies are needed to clarify the regulatory mechanisms governing COX-2 overexpression in colorectal cancers.
Lim
Sung-Chul
SC
Department of Surgery, Chosun University College of Medicine, 375 Seosuk- dong, Dong-gu, Gwangju 501-759, Korea.
Lee
Tae-Beum
TB
Choi
Cheol-Hee
CH
Ryu
So-Yeon
SY
Kim
Kyung-Jong
KJ
Min
Young-Don
YD
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D000368:Aged; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
D016159:Tumor Suppressor Protein p53; D051546:Cyclooxygenase 2