Drug Mechanism Group (DMG) - The Drug Mechanism Group (DMG) provides dedicated support to the Biological Testing Branch, DTP, NCI. The DMG is responsible for determining the mechanism of action and identifying potential surrogate markers of drug activity for a select number of compounds slated for preclinical development using microarray- and proteomic-based platforms. Inclusive in the proteomics technology are quantitative, subcellular, chemical, and 2D-PAGE proteomics. Validation technology is extensive and includes diverse technologies such as cell-based assays, enzymatic assays, ELISA, flow cytometry, quantitative RT-PCR, Western blot analysis, immunohistochemistry, and various microbiological based assays such as transient/stable transfection assays. Specialized Assays Laboratory (SAL) - The Specialized Assays Laboratory (SAL) provides dedicated support to the Biological Testing Branch. SAL is responsible for: (1) providing soft agar colony formation assays in support of cancer stem cell identification and characterization studies in collaboration with other groups within DTP and NCI and (2) employing novel approaches to characterizing the in vivo tumorigenicity of cancer stem cells grown in athymic and NOD.SCID mice Stromal Targets Laboratory (STL) - The Stromal Targets Laboratory (STL) provides dedicated support to the Biological Testing Branch (BTB) through its molecular targets program. Staff members are skilled in such varied technology as Western blots, flow cytometry, ELISA and other microtiter plate-based arrays such as Meso Scale Discovery Technology. Through collaboration with the BTB, differences between molecular targets identified in lysates prepared from cells in culture, cells harvested from implanted hollow fibers, tumor tissue, or normal tissue are being studied. The goal of these studies is to design in vivo and in vitro assays that better predict the activity and eventual success of a drug/compound before it goes to the clinic. The STL is involved in the Phase 0 clinical trial effort, providing evidence of the effect of new therapeutic agents on their putative targets.