NQO1 and cancer: siRNA-mediated knockdown of c-Fos (sic-Fos transfection) increased the proportion of cells at G2/M phase in NQO1-expressing cancer cells compared with that in the siCont-transfected group (Figure 4I,J, middle panel), an effect that was rescued by reintroduction of CKS1B (Figure 4I,J, middle panel).