Smooth muscle cancer cells. Coloured scanning electron micrograph (SEM) of cancer cells from a leiomyosarcoma (cancer of smooth muscle). Cancer cells divide rapidly in a chaotic, uncontrolled manner. They may clump to form tumours that invade and destroy surrounding tissues. Leiomyosarcomas most commonly affect the uterus, stomach and small intestine. They are the second most common sarcoma (connective tissue cancer) affecting soft tissues. Treatment includes surgical excision of the affected areas. Radiotherapy and chemotherapy have poor success rates. Magnification: x1650 at 6x7cm size.