“Migrant studies also provide clues to the origins of cancer. When immigrants arrive in their adopted country, they leave behind the cancer rates of their homelands and quickly equilibrate with the rates of their new surroundings. ‘The most important single conclusion to derive from migrant studies,’ states the International Agency for Research on Cancer, ‘is that, for a group as a whole, it is the new “environment” that determines cancer risk and not the genetic component associated with the ethnic stock of the migrants.’ The quotation marks around that stretchy word ‘environment’ call attention to its many elements: dietary habits, cultural attitudes about breastfeeding, social stress, and opportunities for physical activity are all part of our environment. So, too, are chemical pollutants in air, food, and water.”

Steingraber, Sandra. Living Downstream: An Ecologist’s Personal Investigation of Cancer and the Environment (p. 62). Da Capo Press. Kindle Edition.