Discrepancy between the in-vivo and in-vitro drug sensitivity patterns of human turnout cells has been reported many times.It is often observed that drug screening tests show major differences in in-vitro culture as compared to subsequent in-vivo studies or therapeutic results in patients.This is likely caused by differences in the environmental conditions in-vivo and in-vitro.Unlike cell lines, primary human tumours are particularly sensitive for oxidative stress which can be caused by exposing them to air during sample taking and culturing.Another important issue is the culturing media which is lacking the important growth factors as compared to the in-vivo environment.We aim to decrease this gap by using many new factors which simulates in vivo conditions as closely as possible.We have shown that our screening system is superior to support survival of primary tumours as well as to decrease the sensitivity of tumour cells to most commonly used cytotoxic drugs.We use this method to determine the drug sensitivity pattern of cancer patients with the aim to provide support for clinicians for assay guided individualized therapy.We have also identified some alternative treatment options for CLL, late stage Hodgkin disease and PTLD.Our system also allows survival assays in mixed cell culture systems e.g.fluorescence NK or CTL killing assays or tumorcell/stromal cell drug sensitivity assays.