More on tumor suppression

The cyclin-dependent kinase inhibitor p27^Kip1 blocks cell division in response to antimitogenic signals, but the precise mechanisms behind this tumor suppression activity has been unclear. In July 31 early online edition of the Proceedings of the National Academy of Sciences Harry Hwang and colleagues at the Fred Hutchinson Cancer Research Center, Seattle, US, show that p27^Kip1 collaborates with a number of newly identified oncogenes to induce tumor suppression.

Hwang et al. used a high-throughput strategy to sequence 277 viral insertion sites derived from two distinct sets of p27^-/- mice with lymphomas and determined their chromosomal location by comparison with the Celera and public (Ensembl) mouse genome databases. They observed a "remarkable number of putative protooncogenes in these lymphomas", which included loci that were novel as well as those that were over represented in p27^-/- tumors.

They also showed that Myc activations occurred more frequently in p27-/- lymphomas than in p27+/+ ...