POSTN and neoplasm: Before chemotherapy, E-cadherin is present at cell-cell junctions in most tumor cells and periostin, a secreted extracellular protein, is largely localized at the edge of tumor islands; while residual tumors after treatment with paclitaxel (PTX), doxorubicin (DXR) and cyclophosphamide (CPA) showed downregulation of E-cadherin and upregulation of periostin (Fig. 2A; Supplementary Fig. S1E).