Figure 4a shows an example for the GRB of FOXD3. Human FOXD3, a forkhead transcription factor gene upregulated in chronic myeloid leukemia, Jurkat T-cell leukemia and teratocarcinoma cell lines [37], lies within a GRB harboring a dozen other genes and a cluster of HCNEs, all mapping to a single syntenic locus in all teleost genomes (Figure 4a). This evidence concerns the gene FOXD3 and T-cell leukemia.