 The t(12;21) produces the gene fusion ETV6/RUNX1 and is a frequent rearrangement in childhood ALL, associated with a good prognosis.     ///    "Seventy-one bone marrow samples were analyzed with FISH, using ETV6/RUNX1 DNA probes. "    ///    "Six showed ETV6/RUNX1 fusion and 17, with extra RUNX1 copies, presented an additional chromosome 21 or dup(21)(q22). "