Cyclooxygenase-2 (COX-2) overexpression is associated with a poor prognosis in chondrosarcomas Makoto Endo, 1 Tadaki Matsumura, 2 Umio Yamaguchi, 1 Fumihiko Nakatani, 1 Akira Kawai, 1 Hirokazu Chuman, 1 Yasuo Beppu, 1 Tadashi Hasegawa 2 1 Division of Orthopaedic Oncology, National Cancer Center Hospital, Tokyo, Japan 2 Department of Clinical Pathology, Sapporo Medical University School of Medicine, Sapporo, Japan Sapporo, Japan 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

Background Chondrosarcoma The second most common malignant bone tumor A broad array of presentations The histologic grade is the standard for predicting the outcome 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

he The histologic grading system is separated into three grades Based on 1. cellularity 2. nuclear atypia 3. pleomorphism 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 Grading of chondrosarcomas Fletcher CDM, et al (eds): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Soft Tissue and Bone, 2002.

In some borderline cases, exact histologic grading is difficult using only routine histopathologic examinations 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 Grade 1 Grade 3 Grade 2

Cyclooxygenase-2 (COX-2) An isoform of COX A key enzyme that catalyzes the synthesis of prostaglandins (PGs) from arachidonic acid COX-2-derived PGs play an important role in carcinogenesis 1. induce angiogenesis 2. inhibit apoptosis and immune surveillance 3. increase invasion and metastatic potential 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

investigate the expression profile of To investigate the expression profile of COX-2 using immunohistochemical staining COX-2 using immunohistochemical staining in formalin-fixed, in formalin-fixed, paraffin-embedded chondrosarcoma specimens To confirm whether COX-2 expression is To confirm whether COX-2 expression is associated with prognosis associated with prognosis 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 Purpose

Materials & Methods 74 patients Sex: men, 37; women, 37 Age: y/o (median, 50 y/o) Size: cm (median, 8.0 cm) 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

Location: Axial skeleton, 47 (pelvis, 20; rib, 19; vertebra, 4; scapula, 3; skull base, 1) Long bones, 27 (femur, 10; humerus, 5; tibia, 5; fibula, 2; ulna, 1; others, 4) 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

A monoclonal anti-COX-2 antibody (clone CX-294; 1:100; DakoCytomation) Definition of overexpression: More than 10% of the tumor cells stained 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 Immunohistochemical analysis of COX-2

12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 COX-2 staining in the chondrosarcomas was consistently observed in atypical chondrocytes consistently observed in atypical chondrocytes with a strong and cytoplasmic pattern with a strong and cytoplasmic pattern

12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 ＜ 10% of cells stained = Negative ≧ 10% of cells stained = Positive

Results (74 cases) Histologic grade Grade 1: 39 Grade 2: 32 Grade 3: 3 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 COX-2 overexpression Positive: 16 (22%) Negative: 58 (78%)

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Months Cumulative Disease-specific Survival (%) COX-2 overexpression (+) COX-2 overexpression (-)

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Discussion The first immunohistochemical evidence that COX-2 overexpression is significantly associated with decreased survival 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

Discussion In the multivariate analysis, the only independent risk factor for a poor outcome was a high histologic grade. COX-2 overexpression was significantly associated with the histologic grade. 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

Discussion COX-2 overexpression can be definitively COX-2 overexpression can be definitively evaluated evaluated based on the proportion of stained tumor cells, enabling the subjectivity of interpretations to be minimized. 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

Conclusion COX-2 overexpression in chondro- sarcomas is a useful predictor of patient outcome that is strongly associated with histologic grade. 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006

Acknowledgements Orthopaedic oncology Yuki Morimoto Yoshiyuki Suehara Eisuke Kobayashi Ken Takeda 12 th CTOS Annual Meeting in Venice, Italy 2-4, November, 2006 Pediatric oncology Ako Hosono Pathology Kunihiko Seki Secretarial assistance Yuriko Kawaguchi