Cyclooxygenase-2 expression does not correlate with outcome in osteosarcoma or rhabdomyosarcoma.
OBJECTIVE
To determine if expression of cyclooxygenase (COX)-2, an inducible enzyme with known tumor-promoting activity, correlates with outcome in pediatric sarcomas. COX-2 overexpression correlates with more aggressive disease in a variety of adult solid tumors.


METHODS
Archived human osteosarcoma, rhabdomyosarcoma, and Ewing sarcoma tumors were retrospectively evaluated, blinded to outcome, for COX-2 expression by immunohistochemistry and correlated with patient characteristics and survival.


RESULTS
COX-2 expression was detected in 94 of 142 (66%) tumors (osteosarcoma, 66/99 [67%]; rhabdomyosarcoma, 21/35 [60%]; Ewing sarcoma, 7/8 [88%]) and 51 of 85 (60%) diagnostic biopsies (osteosarcoma, 26/45 [58%]; rhabdomyosarcoma, 21/35 [60%]; Ewing sarcoma, 4/5 [80%]). COX-2 expression did not vary with clinicopathologic features and was not predictive of prognosis in these cases.


CONCLUSIONS
This study does not support the use of COX-2 expression as an upfront prognostic variable in patients with osteosarcoma or rhabdomyosarcoma. Results from the small number of patients studied with Ewing sarcoma suggest a similar lack of predictive value for COX-2 expression. However, COX-2 inhibitors are not entirely dependent upon enzyme expression for their antitumor effects; this study does not necessarily preclude the use of COX-2 inhibitors for the treatment of pediatric sarcomas.
Dickens
David S
DS
Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
Kozielski
Rafal
R
Leavey
Patrick J
PJ
Timmons
Charles
C
Cripe
Timothy P
TP
D000328:Adult; D001859:Bone Neoplasms / Q000201:enzymology* / Q000401:mortality; D051546:Cyclooxygenase 2; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000032:analysis*; D015993:Life Tables; D008175:Lung Neoplasms / Q000201:enzymology / Q000556:secondary; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D009820:Ohio / Q000453:epidemiology; D012516:Osteosarcoma / Q000201:enzymology* / Q000401:mortality / Q000556:secondary; D011379:Prognosis; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis*; D012189:Retrospective Studies; D012208:Rhabdomyosarcoma / Q000201:enzymology* / Q000401:mortality; D012512:Sarcoma, Ewing / Q000201:enzymology* / Q000401:mortality; D012983:Soft Tissue Neoplasms / Q000201:enzymology* / Q000401:mortality; D016019:Survival Analysis; D013781:Texas / Q000453:epidemiology; D016896:Treatment Outcome
D007527:Isoenzymes; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases