Figure 2
Tumour fragments of ccRCC engraft more efficiently than single cell suspensions in NSG mice.
(A) Left panel: Mice were injected under the renal capsule with ex vivo ccRCC single cell suspensions with cell doses ranging from 100 to 2 million. The minimum dose for successful tumour initiation ranged from 1 × 105 to 1 million cells. Each marker represents an individual injected mouse; red circles represent successful xenografts, crosses xenografts that failed to form. Middle panel: Table of pooled results showing engraftment rates (# of mice engrafted/# of mice injected) at each dose. Only doses for which >10 mice per dose were injected were included. Right panel: A Poisson statistics calculation of the pooled data indicates an average TIC frequency of 1 in 2 million (confidence interval 1 in 1.4 million to 1 in 2.9 million, n = 33 patients). Horizontal line indicates the estimated TIC frequency and the bars indicate 95% confidence intervals. These data suggest that TICs in ccRCC are very rare. (B) 1 mm3 tumour fragments of ccRCC engraft more efficiently than high dose single cell suspensions in NSG mice. Comparison of matched samples injected as tumour fragments and single cell suspensions. Area of circle in top graph represents calculated volume of tumour. Tumours that were unable to engraft as single cell suspensions were often able to engraft as fragments.
