ZWILCH and cancer: ZWILCH is an essential component of the mitotic spindle assembly checkpoint necessary for pausing metaphase transition to anaphase until chromosomes are properly attached to the kinetochore.66 Overexpression of ZWILCH and other related mitotic checkpoint proteins has been previously associated with cancer progression,67-69 and there is a strong negative correlation between ZWILCH mRNA levels and patient survival in the SU2C dataset6 (Figure S4E).