Nutlins are cis-imidazoline analogs which inhibit the interaction between mdm2 and tumor suppressor p53, and which were discovered by screening a chemical library by Vassilev et al. Nutlin-1, nutlin-2, and nutlin-3 were all identified in the same screen; however, Nutlin-3 is the compound most commonly used in anti-cancer studies. Nutlin small molecules occupy p53 binding pocket of MDM2 and effectively disrupt the p53–MDM2 interaction that leads to activation of the p53 pathway in p53 wild-type cells. Inhibiting the interaction between mdm2 and p53 stabilizes p53, and is thought to selectively induce a growth-inhibiting state called senescence in cancer cells. These compounds are therefore thought to work best on tumors that contain normal or "wild-type" p53. Nutlin-3 has been shown to affect the production of p53 within minutes.