title: Clinical correlations of drug sensitivity in the human tumor stem cell assay.
abstract: We have applied an in vitro soft-agar tumor-colony assay (which is now applicable to a variety of human cancers) to measurement of in vitro sensitivity to drugs and prediction of clinical response to cancer chemotherapy. The assay predicts drug resistance with 96% accuracy and sensitivity (in healthy pretreated patients) with 62% accuracy. On a pharmacokinetic basis the zone in vitro sensitivity for any given drug was only 5%-10% of the clinical concentration-time product (Cxt) achievable. This suggests that intratumoral drug concentrations in vivo may be lower than those in the plasma, and/or that > 2 log kills of tumor stem cells (not measurable in the assay) are required for clinical response. Serial in vitro studies showed that acquisition of drug resistance is a common clinical phenomenon which can be directly detected and quantitated in vitro.
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003114:Colony-Forming Units Assay; D004351:Drug Resistance; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents