Utility of immunohistochemical analysis for cyclo-oxygenase 2 in the differential diagnosis of osteoblastoma and osteosarcoma.
OBJECTIVE
To study the immunoexpression of cyclo-oxygenase (COX) 2 in osteoblastomas (OBs) and osteosarcomas (OSs), and to assess the utility of immunohistochemical analysis for COX 2 in the differential diagnosis of the two tumour forms.


METHODS
The immunohistochemical features of COX 2 were studied in 11 OBs and 30 OSs, including 26 high-grade OSs (16 osteoblastic, 7 chondroblastic, and 3 fibroblastic) and 4 low-grade OSs.


RESULTS
Tumour cells from all 11 OBs unequivocally showed diffuse, intense and cytoplasmic immunoreactivity for COX 2. Strong cytoplasmic expression of COX 2 was observed in 5 of 26 (19%) high-grade OSs, all chondroblastic. In one osteoblastic-type OS, COX 2 was expressed in the chondroblastic component, but this tumour was considered to be COX 2 negative. No COX 2 expression was noted in atypical osteoblastic cells. Staining in the four low-grade OSs was negative.


CONCLUSIONS
The results of immunohistochemical analysis of COX 2 suggest that in addition to the routine histopathological evaluation, COX 2 is a valuable diagnostic marker in the distinction between OB and OS.
Hosono
Ako
A
Division of Paediatric Oncology, National Cancer Center Hospital, Tokyo, Japan.
Yamaguchi
Umio
U
Makimoto
Atsushi
A
Endo
Makoto
M
Watanabe
Atsuko
A
Shimoda
Tadakazu
T
Kaya
Mitsunori
M
Matsumura
Tadaki
T
Sonobe
Hiroshi
H
Kusumi
Tomomi
T
Yamaguchi
Takehiko
T
Hasegawa
Tadashi
T
D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000473:pathology; D002648:Child; D004796:Clinical Enzyme Tests / Q000379:methods*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D018215:Osteoblastoma / Q000175:diagnosis* / Q000473:pathology; D012516:Osteosarcoma / Q000175:diagnosis* / Q000473:pathology
D014408:Biomarkers, Tumor; D051546:Cyclooxygenase 2