Effect of nocodazole on p21 deficient human colorectal cell lines. Wild-type, heterozygous (p21+/−), and two different homozygous p21-deficient cell lines were treated as described in Fig 8and then cell cycle analysis was performed. G0/G1 exit was calculated as in Table 1. Mean ± SD from three separate experiments are shown. *Statistically significant difference from wild-type response (P < .05).