Zebrafish larvae injected at the one-cell stage with rag::-cMyc+rag::-eGFP were screened for primary leukemia growth 28 days post-injection. Fish (*) had GFP-positive T-cells within the thymus; this fish will develop T-ALL as the T-cells become transformed over time. This stage is very common at day 28. One fish (**) had an advanced T-ALL that has spread into the soft tissue. The remaining two fish are negative for tumor growth. The image was taken at 16X magnification.

Zebrafish were examined for leukemia growth 28 days after transplant. Fish are either tumor negative (A), have a small tumor growing at the injection site (B), or have a progressed leukemia (C). The images were taken at 7X magnification. The total number of leukemia-positive fish per total number of fish transplanted at each dilution is recorded, as in (D). The data are input into the web-based ELDA program to calculate the number of self-renewing leukemia cells and the upper and lower 95% confidence intervals (E).