[SandyBB]

The article states:

Now, breast specialists in particular are reporting an increasing number of women who beat back cancer elsewhere in the body, only to have it flare in the brain. It seems to be a special concern among users of Herceptin, a powerful drug that targets an aggressive type of breast cancer _ everywhere except in the brain, because it's too large a molecule to penetrate the blood-brain barrier, explains Lieberman.

I never realized this! Bummer...