['We examined an economical method for evaluating the amplification of the human epidermal growth factor receptor 2 (HER2) gene in breast cancer specimens.', 'We compared HER2 amplification determined by fluorescence in situ hybridization (FISH) on whole-tissue (WT) blocks used for diagnostic and on tissue microarray (TMA) sections for a cohort of 521 consecutive patients with breast cancer. In a subset of 116 patients, we examined HER2 concordance from the WT section and a TMA section from a randomly chosen additional block (a proxy of the core biopsy).', 'Overall concordance for HER2 amplification between WT and TMA sections was 98.2%, and between sections from WT and from the additional block was 99.0%.'] Does tissue Microarray be a Reliable Tool for the Evaluation of HER2 Amplification in Breast Cancer?