Freebase(0.00 / 0 votes)Rate this definition: Arbol is a programming language which has been primarily developed for use in Genetic Programming experiments. It is a functional programming language inspired by the ideas of other small and esoteric languages.
Causes. In most cases of colon or rectal cancers, the cause or causes are unknown. Defects in genes that normally protect against cancer play the major role in causing polyp cells to continuously change and become cancerous.
Researchers believe that the causes may include: 1  Medications that can irritate the lining of the colon. 2  Bacteria that produce toxins that irritate the lining of the colon. 3  Viruses that trigger inflammation.  Autoimmune disease associated with microscopic colitis, such as rheumatoid arthritis or celiac disease.