RESUMEN
The t(1;11)(p32;q23) translocation is a rare but recurrent cytogenetic aberration in acute myeloid leukemia (AML) and B-cell acute lymphoblastic leukemia (B-ALL). This translocation was initially shown to form a fusion gene between KMT2A exon 8 at 11q23 and EPS15 exon 2 at 1p32 in AML. Activating mutations of FLT3 are frequently found in AML but are very rare in ALL. Here, we describe a 75-year-old woman who was diagnosed with B-ALL since her bone marrow was made up of 98.2% lymphoblasts. These blasts were positive for CD19, CD22, CD79a, CD13, and CD33 but negative for CD10 and myeloperoxidase. The karyotype by G-banding and spectral karyotyping was 46,XX,t(1;11)(p32;q23). Expression of KMT2A/EPS15 and reciprocal EPS15/KMT2A fusion transcripts were shown: KMT2A exon 8 was in-frame fused to EPS15 exon 12, indicating that this fusion transcript was a novel type. Considering three reported B-ALL cases, EPS15 breakpoints were markedly different between AML (exon 2) and B-ALL (exons 10-12). Furthermore, an uncommon type of FLT3 mutation in the juxtamembrane domain was detected: in-frame 4-bp deletion and 10-bp insertion. Accordingly, our results indicate that the novel type of KMT2A/EPS15 fusion transcript and FLT3 mutation may cooperate in the pathogenesis of adult B-ALL as class II and class I mutations, respectively.
Asunto(s)
Cromosomas Humanos Par 11/genética , Cromosomas Humanos Par 1/genética , Mutación/genética , Proteínas de Fusión Oncogénica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Translocación Genética , Tirosina Quinasa 3 Similar a fms/genética , Anciano , Secuencia de Aminoácidos , Secuencia de Bases , Células de la Médula Ósea/patología , Forma de la Célula , Resultado Fatal , Femenino , Humanos , Proteínas de Fusión Oncogénica/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Tirosina Quinasa 3 Similar a fms/químicaRESUMEN
A 71-year-old male smoker was referred to our hospital because of increased hemoglobin and hematocrit. At initial consultation, his hemoglobin and hematocrit levels were 21.8 g/dl and 64.8%, respectively. Other laboratory data and his cardiopulmonary functions were almost normal, and JAK2 V617F mutation was negative. He had smoked about 25 cigarettes per day for 50 years until the age of 70, when he switched from conventional smoking to electronic cigarettes (e-cigarettes). We requested that he quit e-cigarette use. Thereafter, his hemoglobin and hematocrit gradually decreased and normalized. Here, we report the first case of e-cigarette-induced polycythemia.
