PARP1 and neoplasm: In this review article, EMT-mediated mechanisms leading to therapy resistance in tumor cells include the following mechanisms: decreased cisplatin influx mediated by the copper transporter 1 (CRT1), an increased outflow of drugs, increased DNA damage repair, capacity by activating the PARP enzyme, inhibited p53-mediated cell apoptosis signals, changes in cell cycle, changes in different cellular pathways like TGFβ-SMAD, JAK/STAT.