According to Dr.Colgan in his book, You Can Prevent Cancer, resent research shows that carotenoids have an important anti-cancer function. By increasing the flow of regulatory signals, carotenoids can enhance the communication between cells. Normal cells can use this enhanced communication to talk to cells damaged by carcinogens, this will prevent the damaged cells from turning malignant. This communication also inhibits proliferation of already malignant cells. Our bodies produce malignant cells daily that can proliferate into cancer. According to Colgan’s book, carotenoids provide strong protective mechanism to keep these cell under contro.
The Paleo diet contains plenty of vegetables and fruit, just make sure that you include lots of carotenoids. List of fruit and vegetables high in carotenoids found here.
Source: You Can Prevent Cancer, Michael Colgan, PhD.