RAC3 and neoplasm: In addition to their ability for tumor regeneration and in vitro growing as spheroids [35], these cells are the most resistant to chemotherapeutic drugs, being the high MDR expression at least one of the reasons [32, 36], in agreement with our previous works demonstrating that cells overexpressing RAC3 are more resistant to apoptosis, senescence and autophagy [16, 18–20].