Significance of Cox-2 expression in rectal cancers with or without preoperative radiotherapy.
OBJECTIVE
Radiotherapy has reduced local recurrence of rectal cancers, but the result is not satisfactory. Further biologic factors are needed to identify patients for more effective radiotherapy. Our aims were to investigate the relationship of cyclooxygenase-2 (Cox-2) expression to radiotherapy, and clinicopathologic/biologic variables in rectal cancers with or without radiotherapy.


METHODS
Cox-2 expression was immunohistochemically examined in distal normal mucosa (n = 28), in adjacent normal mucosa (n = 107), in primary cancer (n = 138), lymph node metastasis (n = 30), and biopsy (n = 85). The patients participated in a rectal cancer trial of preoperative radiotherapy.


RESULTS
Cox-2 expression was increased in primary tumor compared with normal mucosa (p < 0.0001), but there was no significant change between primary tumor and metastasis. Cox-2 positivity was or tended to be related to more p53 and Ki-67 expression, and less apoptosis (p < or = 0.05). In Cox-2-negative cases of either biopsy (p = 0.01) or surgical samples (p = 0.02), radiotherapy was related to less frequency of local recurrence, but this was not the case in Cox-2-positive cases.


CONCLUSIONS
Cox-2 expression seemed to be an early event involved in rectal cancer development. Radiotherapy might reduce a rate of local recurrence in the patients with Cox-2 weakly stained tumors, but not in those with Cox-2 strongly stained tumors.
Pachkoria
Ketevan
K
Department of Oncology, Institute of Biomedicine and Surgery, University of Linköping, Linköping, Sweden.
Zhang
Hong
H
Adell
Gunnar
G
Jarlsfelt
Ingvar
I
Sun
Xiao-Feng
XF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D012004:Rectal Neoplasms / Q000201:enzymology* / Q000473:pathology / Q000532:radiotherapy*
D009363:Neoplasm Proteins; D051546:Cyclooxygenase 2