TCF3 and acute lymphoblastic leukemia: Recently, using the new genomic inverse PCR for exploration of ligated breakpoints (GIPFEL) technique to identify chromosomal translocations at the DNA level, the incidence of the most frequent first hit in pediatric ALL, the ETV6-RUNX1 fusion, was estimated to be very high: affecting about 5% of healthy newborns, while the incidence of TCF3-PBX1 fusion was 0.6% [7,8].