2. The breast tumors must be ER positive: more than 1% of stained tumor cells by IHC, and HER2 negative: 0, or 1+ score by IHC, or 2+ with FISH/CISH negative for HER2 amplification (defined as a ratio of HER-2/neu copies to chromosome 17 centromere (CEP17) signals <1.8), according to the local laboratory).