MIB1 and osteosarcoma: The fraction of proliferating tumorcells in the investigated series of osteosarcomas ranged from 5% through 90%.This represents a larger range than that obtained in some studies [10, 24–26],but corresponds to the figures reported by German investigators [27, 28].We used the TSA technique to improve the often rather weak immunohistologicalstaining for MIB-1, which may explain our higher range of osteosarcoma cells inproliferation cycle.