Dividing bone cancer cell. Coloured scanning electron micrograph of an osteosarcoma cancer cell undergoing mitosis (nuclear division) and splitting into two daughter cells (left and right), showing the numerous filopodia (hair-like) covering its surface. Osteosarcoma is an aggressive malignant neoplasm arising from primitive transformed mesenchymal cells. It is the most common histological form of primary bone cancer. Magnification: x1800 when printed at 10 centimetres wide.