Professor Douglas Hanahan explains that not only are there positive signals that tell cells to grow but there are negative signals to stop such proliferation, and loss of the negative growth control signals is a common denominator for many cancers.

In 2000, Douglas Hanahan (shown below) and Robert Weinberg published a paper in Cell, "The Hallmarks of Cancer," which identified some organizing principles of cancer cell development. “Not only are there positive signals that say grow but there are brakes which serve normally to stop such proliferation. And the loss of these growth control signals, these negative growth controls is again a common denominator for many cancers and this is separable in some sense from the growth stimulation, it's very much like putting your foot on the gas pedal, you put your foot on the gas pedal, the engine revs up, but if you've got your foot on the brake you still may not go anywhere. So these again are conceptually although they both relate to the ability of the cell to divide continuously they each have separable capabilities.”

negative signals, common denominator, foot on the gas, cancer cell, professor douglas, hallmarks, cancers, proliferation, brakes, cells