Ware Alisha D, Wake Laura, Brown Patrick, Webster Jonathan A, Smith B Douglas, Duffield Amy S
Department of Pathology, Johns Hopkins University, Baltimore, MD.
Department of Oncology, Johns Hopkins University, Baltimore, MD.
AJSP Rev Rep. 2019 Sep-Oct;24(5):191-195.
Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder characterized by a reciprocal translocation, t(9;22) (q34.1;q11.2). This leads to fusion of the and genes, encoding an active tyrosine kinase that causes unregulated proliferation of the myeloid lineage. The BCR/ABL1 fusion protein is found not only in CML, but also in a subset of de novo B-lymphoblastic leukemia (B-LL). However, the fusion protein in CML is characteristically the slightly longer p210 variant, whereas the p190 variant is more frequently found in B-LL. Without treatment, CML will progress to accelerated and/or blast phase (BP). Disease progression is often characterized by accumulation of additional chromosomal abnormalities. The development of tyrosine kinase inhibitor (TKI) therapy that targets BCR/ABL1 has revolutionized treatment of CML and vastly improved outcomes, although the disease can still progress despite TKI therapy. Blast phase most commonly manifests as myeloid BP; however, up to 30% of BP presents as lymphoid BP (LBP), typically of the B-cell lineage. The B-lymphoblasts of LBP have a phenotype indistinguishable from that of de novo B-LL. However, LBP typically carries the p210 BCR/ABL transcript and may show distinct chromosomal anomalies, including loss of chromosome 9p. The prognosis for CML-BP is poor, although survival has improved with TKI therapy and stem cell transplant, and LBP has been associated with superior survival compared with myeloid BP. Here we present a case of CML in B-lymphoid BP and review the current literature.
慢性髓性白血病（CML）是一种克隆性造血干细胞疾病，其特征为9号和22号染色体相互易位，即t(9;22) (q34.1;q11.2)。这导致BCR和ABL基因融合，编码一种活性酪氨酸激酶，该激酶会引起髓系细胞系的不受控制的增殖。BCR/ABL1融合蛋白不仅存在于CML中，也存在于一部分新发B淋巴细胞白血病（B-LL）中。然而，CML中的融合蛋白典型地是稍长的p210变体，而p190变体在B-LL中更常见。未经治疗，CML会进展为加速期和/或急变期（BP）。疾病进展通常以额外染色体异常的积累为特征。靶向BCR/ABL1的酪氨酸激酶抑制剂（TKI）疗法的发展彻底改变了CML的治疗方式并极大地改善了治疗结果，尽管尽管有TKI治疗，疾病仍可能进展。急变期最常见的表现为髓系急变；然而，高达30%的急变期表现为淋巴系急变（LBP），通常为B细胞系。LBP的B淋巴细胞表型与新发B-LL难以区分。然而，LBP通常携带p210 BCR/ABL转录本，可能显示出独特的染色体异常，包括9号染色体短臂缺失。CML-BP的预后较差，尽管TKI治疗和干细胞移植使生存率有所提高，并且与髓系急变相比，LBP的生存率更高。在此，我们报告一例B淋巴系急变期的CML病例并回顾当前文献。
