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.
Pony of the Americas. The Pony of the Americas (POA) is a pony breed developed in the state of Iowa in the United States. The foundation stallion was an Arabian/Appaloosa/Shetland pony cross. A breed registry was founded in 1954, and within 15 years had registered 12,500 ponies. Today, the Pony of the Americas Club is one of the largest and most active youth-oriented horse breed registries in the US.