Prostate cancer. Coloured scanning electron micrograph (SEM) of freeze-fractured tissue from a prostate tumour. The spherical structures (one at lower right) are acini, secretory structures. They are lined with cancerous cells. The prostate gland lies below the bladder. Prostate cancer is one of the most common male cancers, usually affecting the elderly. The uncontrolled growth of the cancer obstructs the neck of the bladder and can impair urination. Treatment involves surgical removal, or radiotherapy. Magnification: x550 at 6x7cm size.