ERBB2 and neoplasm: Indeed, an impressive increase of the pCR rate with the PET regimen was obtained in patients with ER negative (27.5 vs 5.4%) and/or HER2/neu positive tumour (31 vs 5%), while the activity of the two regimens was comparable in patients with ER positive (7.5 vs 7%) and/or HER2/neu negative tumour (10 vs 6%).