MYC and cancer: Similar to the results with human cancer cell lines (Fig 2B), p31ΔMad2 and two C-terminal deletion mutants, p31ΔC170 and p31ΔC30, defective in Mad2 binding did not inhibit Myc/Ras-induced colony formation, in contrast to wild-type p31comet, indicating loss of inhibitory activity (Fig 3E).