The mechanism was a puzzle for a long time since depletion of the obvious MyoJ motor complex disabled BC constriction but only caused a very minor growth phenotype (Frenal et al., 2017), while depletion of BC scaffolding protein MORN1 is lethal and results in conjoined daughters unable to separate from each other (Heaslip et al., 2010; Lorestani et al., 2010). This evidence concerns the gene MORN1 and breast cancer.