MKI67 and neoplasm: Recently, Racca et al. demonstrated efficient killing capability on cervical adenocarcinomacells of ZnO nanocrystals combined with high-energy US shock waves,even if the role of the piezoelectric effect on cell death remainedunclear in this study.94 A recent in vivo experiment also demonstrated the ability of theUS-BTNPs combination to generate toxic reactive oxygen species (ROS),thus down-regulating the Ki-67 proliferative marker and showing apiezo catalytic tumor eradication potential.57