Leucemia mieloide crónica atípica BCR-ABL1 negativa: reporte de 2 casos / BCR-ABL1 negative chronic myeloid leukemia: report of two cases

BCR-ABL1 negative atypical chronic myeloid leukemia (aCML) is a rare type of myeloproliferative / myelodysplastic syndrome characterized by leukocytosis and proliferation of dysplastic neutrophilic precursors in the absence of positivity for the BCR-ABL1 fusion gene. We report a 66-year-old woman and a 57-year-old man with aCML, who initially presented with general malaise and weight loss, associated with anemia, thrombocytopenia, and leukocytosis with left shift and dysplasia in the neutrophil series. Both evolved unfavorably after admission and died a few days later due to multiple organ failure.

Casos atípicos e14a3 (b3a3) en el gen de fusión BCR-ABL de la leucemia mieloide crónica en Cuba / Rare cases of e14a3 (b3a3) BCR-ABL fusion in chronic myeloid leukemia in Cuba

Introducción: La leucemia mieloide crónica es un desorden clonal maligno de células madres hematopoyéticas pluripotentes que se caracteriza por la presencia del cromosoma Filadelfia, consecuencia de la traslocación cromosómica recíproca entre los brazos largos de los cromosomas 9 y 22. El resultado de esta alteración cromosómica es un gen de fusión que contiene las uniones b2a2 (e13a2) o b3a2 (e14a2). En la mayor parte de los casos, las células de la leucemia mieloide crónica expresan uno de los dos transcritos (b2a2 o b3a2); sin embargo, el 5 por ciento de los pacientes tienen ambos tipos de ARNm como resultado de empalmes alternativos. Se han encontrado otros transcriptos como e19a2, e2a2, e1a3, e6a2, e13a3(b2a3), y e14a3(b3a3), que ocurren con menos frecuencia. Objetivo: Describir el comportamiento de dos pacientes con leucemia mieloide crónica que presentan un trascripto BCR/ABL atípico. Casos clínicos: En el estudio molecular por reacción en cadena de la polimerasa cualitativo realizado a los dos pacientes, se observó un punto de ruptura del gen de fusión BCR/ABL poco frecuente, el cual se correspondía al transcripto e14a3 (b3a3). Estos pacientes iniciaron tratamiento con mesilato de imatinib a dosis de 400 mg diarios. Al primer paciente a los dos meses de tratamiento se le detectó crisis blástica, por lo que se le cambió el tratamiento a nilotinib 400 mg diarios que mantiene hasta la actualidad. La segunda paciente mantuvo igual tratamiento, aunque en ocasiones ha sido necesario incorporar tratamiento citorreductor con hidroxiurea por presentar leucocitosis. Conclusiones: Los pacientes con BCR/ABL a3 presentan un curso más benigno de la enfermedad. Aunque en los pacientes estudiados no se observó una respuesta satisfactoria al tratamiento pues presentaron diversas complicaciones(AU)

Introduction: Chronic myeloid leukemia is a malignant clonal disorder of pluripotent hematopoietic stem cells and characterized by the presence of the Philadelphia chromosome, which is the product of a reciprocal translocation between the long arms of chromosomes 9 and 22. The result of this chromosomal alteration is a fusion gene that contains the e13a2 (b2a2) and e14a2 (b3a2) junctions. In most cases, chronic myeloid leukemia cells express one of the two transcripts (b2a2 or b3a2); however, 5 percent of patients have both types of mRNA, as a result of alternative junctions. Other transcripts have been identified, such as e19a2, e2a2, e1a3, e6a2, e13a3 (b2a3), and e14a3 (b3a3), which occur less frequently. Objective: To describe the behavior of two patients with chronic myeloid leukemia who have an atypical BCR-ABL transcript. Clinical cases: In a qualitative molecular study of polymerase chain reaction carried out with two patients, a BCR-ABL fusion gene breakpoint was observed, which corresponded to the e14a3 (b3a3) transcript. These patients started treatment with imatinib mesylate at a dose of 400mg/d. At two months, the first patient had a diagnose of blast crisis, so the treatment was changed to nilotinib at a dose of 400mg/d, which the patient maintained to date. The second patient maintained the same treatment, although it was sometimes necessary to incorporate cytoreductive treatment with hydroxyurea due to leukocytosis. Conclusions: Patients with BCR-ABL a3 present a more benign evolution of the disease. However, a satisfactory response to treatment was not observed in the patients studied, as long as they presented various complications(AU)

Cytogenetic investigation in chronic myeloid leukemia: study from an Indian population.

Chronic myeloid leukemia (CML) is a malignant neoplasm of hematopoietic cells characterized by abnormal proliferation of myeloid precursors, decreased rates of self destruction and an arrest in cellular differentiation. The bone marrow and peripheral blood accumulates all forms of mature and immature granulocytes, primarily blast cells. It is the most common type of leukemia seen in India, accounting for 30% of all leukemias. Cytogenetic analysis plays a vital and important role in the diagnosis of CML patients. The present study consists of cytogenetic evaluation of 175 CML cases from the Indian population with ages ranging from 6-86 years (mean of 42.8). The study population included 115 males (65.72%) and 60 females (34.28%) with a Male: Female ratio 1.9:1. Out of the 175 cases, 164 (93.7%) were successfully karyotyped while culture failure was observed for 11 (6.3%). Among the 164 reported cases, 53 (32.3%) showed a normal karyotype while within the 111 (67.7%) abnormal cases, 96 cases (86.5%) showed the presence of Philadelphia (Ph') chromosome with standard translocation t(9;22); Ph'+ve along with secondary aberrations was detected in 9 (8.1%) cases. Variants of Ph' chromosome were detected in only one case (0.9%). Ph'-ve CML with other chromosomal aberrations were detected in 5 (4.5%) cases, including +8, del 20q, del 11q and marker chromosome. Furthermore, we believe that availability of more advanced molecular techniques can be used as a supportive tool in CML diagnosis even though it cannot fully replace cytogenetics, which remains the backbone for laboratory investigation of the disease.