Her-2By: Robert Bazell Two years after she underwent a mastectomy and chemotherapy, Barbara Bradfield's aggressive breast cancer had recurred and spread to her lungs. The outlook was grim. Then she took part in Genentech's clinical trials for a new drug. Five years later she remains cancer free. Her 2 is the biography of Herceptin, the drug that provoked dramatic responses in Barbara Bradfield and other women in the trials and that offers promise for