8 It also controls mitotic spindle formation and chromosome segregation by stabilizing kinetochore fibers, thus having an important role in mitotic progression. 9 We demonstrated that the interference of circZNF609, and hence the downregulation of CKAP5 protein levels, produces a de-regulation of microtubule dynamics, leading to abnormal chromosome segregation and DNA damage accumulation, which will eventually produce the cell-cycle halt previously observed in rhabdomyosarcoma. 4 Here, CKAP5 is linked to rhabdomyosarcoma.