PROGNOSTIC SIGNIFICANCE OF PROLIFERATIVE ACTIVITY (KI67 EXPRESSION) IN OSTEOSARCOMA IN CHILDREN

BACKGROUND: Osteosarcoma is the commonest primary malignant bone tumor in children.The treatment involves extensive and sometimes life threatening chemotherapy and mutilating surgery.The study of cell proliferation by Ki67 immunohistochemistry has been extensively analyzed in different cancers as a prognostic marker but little information is available in the field of osteosarcoma.The purpose of this study was to evaluate the expression of Ki67 activity in different histological types and grades of osteosarcoma and to evaluate whether higher Ki-67 expression in osteosarcoma can predict the clinical outcome.METHODS: The study was conducted with 30 patients of osteosarcoma.There were 19 boys and 11girls.The mean age was 12.8 yrs.We received the specimens of incisional biopsy of the suspected lesions.All the patients were treated similarly following diagnosis (chemotherapy, definitive surgery followed by chemotherapy) and they were followed up for 24 months from the date of diagnosis.Histological type and grade were determined by examining the Hematoxylin and Eosin stained slides.Proliferative activity (Ki67 expression) was measured immunohistochemically using MIB-1 antibody.Proliferation was quantitated by counting the number of immunopositive nuclei, detected manually under light microscope.Proliferation index was evaluated in relation to histological grade and survival.RESULTS AND CONCLUSION:We found 12 cases of low grade and 18 cases of high grade osteosarcomas.The mean of Ki67 LI in low grade osteosarcoma was seen 9.9 whereas in high grade osteosarcoma the mean was 21.6.A significant positive correlation between Ki67 LI and histological grade was observed in osteosarcomas (p <0.001).There was no statistically significant correlation found between Ki67LI and the histologic types of osteosarcomas.We followed up all the cases for 24 months; a worse prognosis was observed in osteosarcomas of higher proliferative activity.