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.
This process is called carcinogenesis. Carcinogenesis begins when carcinogens (cancer-causing substances) damage the DNA in a cell (e.g., a genetic mutation) and/or cause changes in other cell components or cell activities that can predispose them to cancer.olon cancer has become a model for studying multi-stage carcinogenesis. Four distinct sequential mutations have been described in the development of colon cancer. These are mutations of the APC (adenomatous polyposis coli), K-ras, DCC (deleted in colon cancer), and p53 genes.