(Ivanhoe Newswire) -- Doctors know cancer begins with a few cells and then grows until it is out of control. But how and why have remained a mystery.

Researchers from Harvard and Johns Hopkins have developed a new mathematical formula they believe will help unravel that mystery and one day make it easier for scientists to understand how cancer develops and grows in the human body – and why some tumors are more deadly than others, despite their size.
 

Using colon cancer as a model, they tracked the development of the disease from a single genetically altered cell to billions of cells, coming up with a model that shows cancer is driven by many different genes, each of which confers only a small advantage of continued survival on that gene.

The take home message from the research is that individual tumors may be caused by as many as 20 different mutated genes, and the time it takes for a benign tumor to become cancerous is driven more by the number of genes involved and the selective advantage per mutation than the size of the tumor or the rate of mutation.

The finding runs counter to typical thinking, which has held that cancer progression relies on only a few genetic mutations.

SOURCE: PLoS Computational Biology, published online Nov. 9, 2007