Rankl expression as a prognostic marker in stage III giant cell tumour of the bone

Introduction: Giant cell tumour of bone is an aggressive benign bone tumor composed of unstable spindle shaped neoplastic mononuclear stromal cells and reactive components osteoclast like giant cells. GCT in Asian population including Malaysia, presented with more aggressive tumour and higher rate o...

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Main Author: Abdul Ghani , Nur Sabrina
Format: Thesis
Language:English
Published: 2015
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Online Access:http://eprints.usm.my/39892/1/Dr_Nur_Sabrina_Abdul_Ghani_%28Orthopaedics%29-24_pages.pdf
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Summary:Introduction: Giant cell tumour of bone is an aggressive benign bone tumor composed of unstable spindle shaped neoplastic mononuclear stromal cells and reactive components osteoclast like giant cells. GCT in Asian population including Malaysia, presented with more aggressive tumour and higher rate of lung metastasis. Although numerous attempts have been made to predict the behavior of GCT, there are no definite biological or histological parameters to determine the prognosis or aggressiveness of this lesion. Objectives: The aim of this study is to determine the presence of RANKL activity in aggressive type (stage III) GCT and its effectiveness as a prognostic marker in predicting risk of local recurrence and lung metastasis in GCT of bone. Material and method: We evaluated 39 cases of stage III GCT of bone for RANKL expression using immunohistochemical staining. There were 21 males and 18 females patients and the mean age was 36.2 (ranged between 11 to 66 years old). Majority of the patients were Malays (85%) followed by Chinese (15%). 46.2% of the tumour occurred at a knee region followed by distal radius (17.9%). 35 out of 39 (90%) patients were treated with wide resection, 3 by intralesional resection and 1 cases of metacarpal GCT with extensive soft tissue involvement were treated by rays amputation. 10% of cases had local recurrence and 20% presented with or eventually developed lung metastasis. 5% of the cases presented with local recurrence and lung metastasis. Expression of RANKL was evaluated by immuno-histochemical staining techniques using the rabbit polyclonal antibody RANKL representing full-length RANKL human origin from Santa Cruz Biotechnology. The scoring was done by counting the positively stained cell in the background of 1000 mononuclear stromal cells. Data was analyzed using PASW version 18.0. Result: RANKL expressions were evaluated by percentage of expression (<25%, 25%-75%, >75%), staining intensity (1 to 3) and final score of the two value (1-2= weak, 3-4= moderate, 5-6= strong). 82% of the sample expressed RANKL >75% from whole stromal cell population. Base on staining intensity, 48% scored 2, and only 23% had maximum intensity (3). 66.6% demonstrate strong RANKL expression. The mean value for RANKL according to percentage of staining, staining intensity and final score was 2.79 (SD 0.47), 1.95 (SD 0.72) and 4.77 (SD 0.99) respectively. The mean percentagestaining between no recurrence and with recurrence group was significantly different (p=0.009). Conclusion: RANKL expression is generally high in stage III GCT and is a reliable prognostic markers in predicting the risk of local recurrence but not in lung metastasis.