PLK1 and breast cancer: To assess the relationship between FBXW7, MCL1 and PLK1 expression and the response to chemotherapy in breast cancer, we performed an analysis of FBXW7, MCL1 and PLK1 expression in two groups of node-negative breast cancer patients treated with FEC (5-Fluorouracil, epirubicin, cyclophosphamide; n = 41) or FEC with paclitaxel (FECP; n = 44).