Factors that contribute to faecal cyclooxygenase-2 mRNA expression in subjects with colorectal cancer.
BACKGROUND
We previously reported that a faecal cyclooxygenase-2 (COX-2) mRNA assay was useful for identifying colorectal cancer (CRC). This study sought to investigate the factors that contribute to faecal COX-2 mRNA expression in subjects with CRC.


METHODS
The study cohort comprised 78 patients with CRC and 36 control subjects. The expressions of COX-2, beta-2-microglobulin (B2M), carcinoembryonic antigen (CEA), E-cadherin (E-cad), and CD45 mRNA in faeces and COX-2 mRNA expression in tissue were determined by quantitative real-time RT-PCR.


RESULTS
The level of faecal expression of COX-2 mRNA in CRC was significantly higher than that in controls. A significant correlation was found between faecal COX-2 mRNA expression and faecal B2M, CEA, E-cad, or CD45 mRNAs, markers of exfoliated total cells, colonocytes, and leukocytes, respectively. A significant correlation was found between the expression of COX-2 mRNA in faeces and tumour surface area, COX-2 mRNA expression in primary tumour. There was no difference in faecal COX-2 mRNA expression between proximal CRC and distal CRC.


CONCLUSIONS
COX-2 mRNA expression in faeces seems to originate from tumour lesion and to be affected by factors such as the number of exfoliated cells, exfoliation of inflammatory cells, COX-2 mRNA expression in tumour, and tumour size.
Hamaya
Y
Y
Department of Molecular Diagnosis, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Japan.
Yoshida
K
K
Takai
T
T
Ikuma
M
M
Hishida
A
A
Kanaoka
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000235:genetics / Q000378:metabolism; D016022:Case-Control Studies; D015331:Cohort Studies; D003106:Colon / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012007:Rectum / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D055815:Young Adult; D001613:beta 2-Microglobulin / Q000235:genetics / Q000378:metabolism
D014408:Biomarkers, Tumor; D015820:Cadherins; D002272:Carcinoembryonic Antigen; D012333:RNA, Messenger; D001613:beta 2-Microglobulin; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human