RESPONSE
We thank Abdo and colleagues1 for their interest in our recent publication2 and for their insights into the cell of origin (COO) of TCF3-ZNF384 and PTPN11 mutations in monozygotic twins with concordant B-cell progenitor-acute lymphoblastric leukemia (BCP-ALL). We are delighted that the conclusions reached by their independent analyses are suggestive of the same underlying conclusions that we reached: the inferred COO is around the onset of immunoglobulin heavy chain (IgH) DJ rearrangement in the bone marrow, likely in a pre-DJ progenitor. Abdo et al raise some important points about the study upon which we can comment and elaborate (Figure 1A).
First, the complex rearrangement leading to the TCF3-ZNF384 fusion resulted from a 3-way t(12;14) and t(14;19) translocation, and we confirmed that the chromosome 14 breakpoint involved the end of the IgH locus, spanning from position 107...
