Pregnancy spurs a tumor suppressor
By Nathan Seppa
Women who undergo a full-term pregnancy at an early age are less likely to develop
breast cancer than are women who never get pregnant. Scientists experimenting with
rodents now have evidence that a cancer-fighting protein called p53 accounts for
this protection.
The researchers propose that estrogen and progesterone, produced in abundance
during pregnancy, alter breast cells in some fundamental way that enables them to
produce ample p53 later in life. This girds cells against substances or various