Oncotest was founded in 1992 and has soon been recognized internationally for its expertise in anticancer drug evaluation. Based on its 20 years’ experience in anticancer research, it has established a unique collection of human tumors from various origins. The tumor collection comprises 120 xenografts permanently growing in nude mice, 350 nitrogen-frozen human tumors and more than 200 tumor cell lines. This allows Oncotest to rapidly screen new compounds for anticancer activity and to select sensitive tumors to broaden the drug development pipeline up to clinical trials. The in vitro and in vivo screens on permanent tumor cell lines (monolayer assay) or human xenografts (clonogenic assay and in vivo studies), as well as target orientated approaches (Gene Chips, Tissue Micro Arrays, Cytometry) and mechanism of action studies enable to stepwise focus on the best lead candidates for the clinic.