Table 1.

Effect of loss of TGF-β response on tumor take rate of Ca1h cells

Initial cell inoculumExperimental tumor take rateCalculated no. tumor initiating cells/million cells
5 × 105105104103
Experiment 1
    Cell genotype
        Ca1h-CON5/55/60/60/68
        Ca1h-DNR5/55/64/61/670–170
Experiment 2
    Cell genotype
        Ca1h-CONND5/50/80/7<12
        Ca1h-DNRND5/53/41/575–200
        Ca1h-Id1ND5/50/40/5<24
  • NOTE: Ca1h cells were transduced with control, DNR, or Id1-expressing retroviruses and then injected into the flanks of nude mice at varying initial cell inocula. Mice were monitored over 3 mo for the appearance of tumors. The relative number of tumor-initiating cells in the population was determined by calculating the minimum cell inoculum required to generate a tumor.

    Abbreviations: CON, control; ND, not determined.