FIG 1.

(A) Bone marrow biopsy at diagnosis with a diffuse infiltrate of medium-sized primitive lymphoid cells consistent with blasts. (B) Multiparameter flow cytometry shows a CD45(dim)CD34(+)CD19(+)CD10(+) immunophenotype. (C) Top: Chromosome analysis showed that 21 of 23 cells contained a reciprocal translocation between chromosomes 9 and 22, with breakpoints in bands 9q34 and 22q11.2, indicative of BCR-ABL1 rearrangement, which was confirmed by fluorescence in situ hybridization. Bottom: Two of 23 cells also demonstrated loss of chromosome 9 and an additional derivative chromosome 22. (D) Remission marrow after treatment with maturing trilineage hematopoiesis. (E) Multiplex polymerase chain reaction–based B-cell clonality studies identified a clonal Igκ gene rearrangement with a monoclonal peak with an electrophoretic mobility of 83.4. (F) B-cell clonality studies on the post-treatment specimen showed an oligoclonal pattern with no evidence of the previously characterized monoclonal Igκ rearrangement. Igκ, immunoglobulin kappa; JK, joining region of the immunoglobulin kappa gene; OL, immunoglobulin lambda light chain.