Table 1. Differences between B-lymphoblasts and myeloid blasts in flow cytometry, cytogenetics, and next generation sequencing studies at the time of diagnosis of B-ALL and post-transformation to AML 9 days following blinatumomab.
| B-ALL at diagnosis | AML at transformation | |
|---|---|---|
| Flow cytometric features of the blasts | Express: CD9, CD15 (partial), CD19, cCD22, CD38, CD45 (dim), cCD79a, HLA-DR, nTdT | Express: CD45, CD13, CD15, CD33, CD56, CD36, CD64 (partial), cMPO |
| Do not express: CD10, CD3, CD13, CD16, CD33, CD117, CD2, CD7, CD56, CD36, CD64, cMPO, cCD3, CD20, CD66c | Do not express: CD34, CD19, CD10, CD3, CD16, CD117, HLA-DR, nTdT, CD2, CD7, CD38, cCD22, cCD79a, cCD3 | |
| Cytogenetics | 46, XX; t(4;11)(q21;q23)[20] | 52,XX,t(4;11)(q21;q23),t(5;19)(p11;q11), +6,+7,+8,+8,+13,+19[cp10] |
| 79-80,XXXX,-1,-2,t(4;11)(q21;q23), der(4)t(4;11),-5,-7,-9,-10,-10,-11,-15,-16, -17,-21,-22[cp9] | ||
| 45,XX,-21[1] | ||
| FISH for KMT2A-AFF1 fusion | 95.60% | 49%a |
| Next generation sequencing (NGS) | MPL: c.1653del; p.Lys553Argfsa77 (48%) | MPL: c.1653del; p.Lys553Argfsa77 (33%) |
| NRAS: c.38G>A; p.Gly13Asp (49%) |
Abbreviations: ALL, acute lymphoblastic leukemia; AML, acute myeloid leukemia; ‘c’, cytoplasmic; FISH, fluorescence in situ hybridization; ‘n’, nuclear; MPO, myeloperoxidase.
NGS genes included ASXL1, BCOR, BRAF, CALR, CBL, CEBPA, CSF3R, DNMT3A, ETV6, EZH2, FLT3, GATA1, GATA2, IDH1, IDH2, JAK2, KIT, KRAS, MPL, MYD88, NOTCH1, NPM1, NRAS, PHF6, PTPN11, RUNX1, SETBP1, SF3B1, SRSF2, TERT, TET2, TP53, U2AF1, WT1 and ZRSR2.
a
FISH was done on a follow-up bone marrow aspirate after patient was initiated on a salvage therapy for AML.