Cancer can be triggered by infectious diseases, especially in impoverished parts of the world. Scientists in the US and Africa are working to unravel how viruses and bacteria cause malignancies. By breaking that cycle, they hope to prevent tumors from forming in the first place.
Public Health is the science of protecting and improving the health of communities through education, promotion of healthy lifestyles, and research for disease and injury prevention.
(What is Public Health? Association of Schools of Public Health )