During the twentieth century wealthy countries underwent a transition in mortality from acute, infectious diseases such as pneumonia to chronic diseases such as cancer. By the late twentieth century the lifetime risk of a person receiving a cancer diagnosis in the United States had climbed above one-in-three. The quest for an elusive "cure" for cancer became a policy imperative, and by the first decade of the twenty-first century U.S. government expenditures on cancer research had reached three billion dollars per year. Notwithstanding decades of heavy research funding, advances in long-term survival for many of the common types of cancer have remained insignificant, and critics have charged that research funding has been too narrowly focused.

Etiologies

The ancient Greeks and Romans understood cancer and other diseases in terms of the bodily humors of phlegm, blood, black bile, and yellow bile (Rather 1978). When the humors were out of balance...