Lung tissue from p27+/+, +/−, or −/− mice was transplanted to the ears of wild type recipients. After engraftment, mice were then treated with urethane and transplant size was measured up to 30 weeks (p27+/+ n=14, p27+/− n=23, p27−/− n=14). (A) Bar graph shows percent transplants that developed tumours. (B) Size of transplanted tumours at 30 weeks. Each symbol represents one transplant.