The immunophenotype data for five of our 12 CML/BC samples that carry concomitant 7p/9p loss (cases 184, 192, 193, 195 & 200, Additional file 12: Table S4) are consistent with early B cell origin of the blast cells (TdT+, CD10+, CD19+, CD22+, CD7 neg, so it could be that the recurrent loss of the TCRG/D region in B cells with legitimate IGH rearrangements represents the lineage infidelity as reported previously in blast phase CML [18-21]. This evidence concerns the gene TRGC1 and chronic myelogenous leukemia, BCR-ABL1 positive.