Where the cancer starts is called the primary tumour. Some types of cancer, called leukaemia, start from blood cells. They don't form solid tumours. Instead, the cancer cells build up in the blood and sometimes the bone marrow. For a cancer to start, certain changes take place within the genes of a cell or a group of cells.
pommel horse. n. 1. A piece of gymnastic equipment that consists of a padded, loaf-shaped object with two pommels on top and stands horizontal to the floor, usually on adjustable legs. 2. An athletic event in which the pommel horse is used.
The pommel, at the front and the cantle, at the rear are made of a solid material, such as wood. The independent pommel/cantle two-piece system lets the horse flex and move freely. The rider keeps complete contact with the horse. The top is finished in leather.