disease
BACKGROUND: Treatment of breast cancer with the antiestrogen tamoxifen is       effective in approximately one half of the patients with estrogen       receptor-positive disease, but tumors recur frequently because of the development       of metastases that are resistant to tamoxifen.
BACKGROUND: Treatment of breast cancer with the antiestrogen tamoxifen is       effective in approximately one half of the  @OBJECT$   @PREDICAT$  estrogen       receptor-positive  @SUBJECT$ , but tumors recur frequently because of the development       of metastases that are resistant to tamoxifen.