Instead just studying cancer itself, more and more researchers are taking into consideration the role of the cellular environment in the development of the disease.
"Some researchers are taking a fresh look at ideas that were dismissed as folklore — a blow to the breast might spur cancer, an infection might fuel cancer cells, a weak immune system might let cancer spread. They also say the new approach may help explain mysteries, like why the breast cancer rate plummeted when women stopped taking menopausal hormones. One answer may be that hormone therapy changes normal cells of the breast and may allow some tiny tumors to escape from the milk ducts where breast cancer starts.
The basic idea — still in the experimental stages — is that cancer cells cannot turn into a lethal tumor without the cooperation of other cells nearby. That may be why autopsies repeatedly find that most people who die of causes other than cancer have at least some tiny tumors in their bodies that had gone unnoticed. According to current thinking, the tumors were kept in check, causing no harm.
It also may mean that cancers grow in part because normal cells surrounding them allowed them to escape. It also means that there might be a new way to think about treatment: cancer might be kept under control by preventing healthy cells around it from crumbling."
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