The 70-gene signature (MammaPrint) is a prognostic tool used to guide adjuvant 
treatment decisions. The aim of this study was to assess its value to predict 
chemosensitivity in the neoadjuvant setting. We obtained the 70-gene profile of 
stage II-III patients prior to neoadjuvant chemotherapy and classified the 
prognosis-signatures. Pathological complete remission (pCR) was used to measure 
chemosensitivity. Among 167 patients, 144 (86%) were having a poor and 23 (14%) 
a good prognosis-signature. None of the good prognosis-signature patients 
achieved a pCR (0/23), whereas 29/144 patients (20%) in the poor 
prognosis-signature group did (P = 0.015). All triple-negative tumors (n = 38) 
had a poor prognosis-signature. Within the non triple-negative subgroup, the 
response of the primary tumor remained associated with the classification of the 
prognosis-signature (P = 0.023). A pCR is unlikely to be achieved in tumors that 
have a good prognosis-signature. Tumors with a poor prognosis-signature are more 
sensitive to chemotherapy.