Median-effect plots demonstrate that cooperation of CD::UPRT/5-FC and HSVtk-MSC/GCV systems is mutually nonexclusive. EGFP-expressing tumor cells were mixed with CD::UPRT-MSC and HSVtk-MSC in ratio 10:1:1 and treated by 5-FC and/or GCV. Data obtained by fluorimetric assay were subsequently analyzed by Calcusyn software. The particular approaches affect different pathways, because the lines representing the efficacy of CD::UPRT-MSC and HSVtk-MSC approaches are convergent. Log(D) = log of dose – concentration of particular prodrugs; log(fa/fu) = log (proportion of dead cells/proportion of viable cells).