Figure 3. In vivo tumour growth initiated by ALDH⁺ and ALDH⁻ cells isolated from Melmet 1 xenografts.

(A) Sorted cells from both subpopulations were injected s.c. (4000, 500 and 200 cells per injection, indicated in the figure) into NOD-SCID Il2rg^−/− mice for formation of 1^st generation tumours (appearance of the tumours is shown in the photographs). P>0.05 at all time points in the comparable groups. (B) The tumours derived from ALDH⁺ and ALDH⁻ cells were resorted into ALDH^+/+, ALDH^+/− and ALDH^−/− subpopulations (see Figure 4), and 1000 viable cells from each subpopulation were reinjected into mice for formation of 2^nd generation tumours. Data represent mean ± SEM of 4–6 tumours. P>0.05 between ALDH^+/+ and ALDH^+/−; p<0.05 between ALDH^+/+ and ALDH^−/− indicated by *.