Where you live has a relationship to your odds of getting cancer and surviving cancer. Epidemiologists studying this link they see in the data have focused on so-called social determinants of health — poor access to transportation, for example, could make it harder for residents to see a doctor. Places lacking grocery stores with fresh food could mean worse nutrition for locals.

Neighborhoods are like ecosystems in their complexity, with countless variables both small and large that could plausibly influence health and biology. For instance, the built environment, whether it has sidewalks or parks or polluting factories, and an area’s crime statistics could influence how easy it is for residents to exercise or spend time outdoors.