Breast cancer cells. Coloured scanning electron micrograph (SEM) of breast cancer cells. The cells shows numerous processes and microvilli (fine surface extensions). These features are characteristic of highly mobile cells, and enable cancerous cells to spread (metastasis) rapidly round the body, and invade other organs and tissues. Cancer cells divide rapidly and chaotically, and may clump to form malignant tumours. The tumours often invade and destroy surrounding tissues. Breast cancer is the most common form of cancer in women. Treatment involves surgical removal of the tumour, often combined with radiotherapy and chemotherapy. Magnification: x1500 when printed 10cm wide.