ABSTRACT
Objective:To investigate the clinical characteristics and prognostic factors of TCF3-PBX1 fusion gene-positive childhood B-cell precursor acute lymphoblastic leukemia (B-ALL).Methods:The clinical data of 1 287 newly diagnosed children with B-ALL who were admitted to five hospital in Fujian province (Fujian Medical University Union Hospital, the First Affiliated Hospital of Xiamen University, Zhangzhou Affiliated Hospital of Fujian Medical University, Quanzhou First Hospital Affiliated to Fujian Medical University, Nanping First Hospital of Fujian Province) from April 2011 to December 2020 were retrospectively analyzed. According to the results of TCF3-PBX1 fusion gene testing, all the patients were divided into TCF3-PBX1-positive group and TCF3-PBX1-negative group. The clinical characteristics, early treatment response [minimal residual disease (MRD) at middle stage and end of induction chemotherapy] and long-term efficacy [overall survival (OS) and event-free survival (EFS)] of the patients in both groups were compared. Kaplan-Meier method was used for survival analysis. The prognostic factors of TCF3-PBX1-positive B-ALL were analyzed by using Cox proportional hazards model. Among 83 children with TCF3-PBX1-positive B-ALL, the treatment regimens, risk stratification and efficacy evaluation of 62 cases were performed by using Chinese Children's Leukemia Group (CCLG)-ALL 2008 regimen and 21 cases were performed by using Chinese Children's Cancer Group (CCCG)-ALL 2015 regimen, and the efficacy and incidence of serious adverse events (SAE) between the two groups compared.Results:Among 1 287 B-ALL patients, 83 patients (6.4%) were TCF3-PBX1-positive. The proportion of patients with initial white blood cell count (WBC)≥50×10 9/L in the TCF3-PBX1-positive group was higher than that in the TCF3-PBX1-negative group, while the proportions of patients with MRD ≥1% on induction chemotherapy day 15 or day 19, and MRD ≥0.01% on induction chemotherapy day 33 or day 46 in the TCF3-PBX1-positive group were lower than those in the TCF3-PBX1-negative group (all P < 0.05). Univariate Cox regression analysis showed that MRD ≥1% on induction chemotherapy day 15 or day 19 and TCF3-PBX1 ≥0.01% on induction chemotherapy day 33 or day 46 were risk factors for OS and EFS (all P < 0.05). Multivariate analysis showed that MRD ≥1% on induction chemotherapy day 15 or day 19 was an independent risk factor for OS ( HR = 10.589, 95% CI 1.903-58.933, P = 0.007) and EFS ( HR = 10.218, 95% CI 2.429-42.980, P = 0.002). TCF3-PBX1≥0.01% on induction chemotherapy day 33 or day 46 was an independent risk factor for EFS ( HR = 6.058, 95% CI 1.463-25.087, P = 0.013) but not for OS ( HR = 3.550, 95% CI 0.736-17.121, P = 0.115). The 10-year EFS and OS rates of the TCF3-PBX1-positive group were 84.6% (95% CI 76.9%-93.1%) and 89.1% (95% CI 82.1%-96.6%), and the differences between the two groups were not statistically significant (both P > 0.05). Among 80 children who received standardized treatment, compared with children who were treated with CCLG-ALL 2008 regimen, the incidence of infection-related SAE was lower in children who were treated with CCCG-ALL 2015 regimen [0 (0/21) vs. 20.3% (12/59), χ2 = 5.22, P = 0.022], but there were no statistical differences in treatment-related mortality, relapse rate, EFS and OS between the two groups (all P > 0.05). Conclusions:Children with TCF3-PBX1-positive B-ALL have a good prognosis, and MRD≥1% at middle stage of induction chemotherapy and TCF3-PBX1≥0.01% at the end of induction chemotherapy may be influencing factors for poor prognosis. CCCG-ALL 2015 regimen can reduce infection-related SAE while achieving good efficacy.
ABSTRACT
La Leucemia Linfoblástica Aguda (LLA) es la neoplasia más frecuente en edad pediátrica. En los últimos años, entre el 15 y 20% de los pacientes fracasan en el tratamiento. Conocimientos en citogenética y biología molecular repercuten de manera importante en la determinación del pronóstico y del esquema de tratamiento adecuado. En Venezuela existe un conocimiento limitado en cuanto a la genética molecular de esta alteración onco-hematológica. El objetivo del trabajo fue evaluar las alteraciones genéticas más frecuentes en pacientes venezolanos con diagnóstico clínico de leucemia linfoblástica aguda. Se realizó un estudio transversal, descriptivo y prospectivo de 2006 a 2014, en el que se evaluaron las translocaciones ETV6/RUNX1, MLL/AF4, TCF3/PBX1, BCR/ABL1, así como las mutaciones en los genes PAX5 y FLT3 mediante el uso de diferentes tipos de PCR. Ciento treinta pacientes con diagnóstico clínico de leucemia linfocítica aguda fueron incluidos en el estudio. Se identificaron alteraciones moleculares en 56 pacientes (43,1%), en los que observamos la presencia de una o varias alteraciones en conjunción en un mismo paciente. Las alteraciones identificadas fueron t(12;21) (11,5%), t(4;11) (8,5%), t(1;19) (10%), t(9;22) (20,8%), ITD-FLT3 (14,8%), mutación P80S (4,2%) y S77del (4,2%) en el gen PAX5. La prevalencia de BCR/ ABL, es una de las más altas que ha sido descrita hasta ahora en casos de LLA donde la mayor parte de la población está conformada por pacientes pediátricos. Estos resultados representan el primer estudio molecular de la LLA en Venezuela, sentando las bases para el diagnóstico y seguimiento de la enfermedad en su población.
Acute Lymphoblastic Leukemia (ALL) is the most common neoplasm in pediatric age. In recent years, between 15 and 20% of patients failed in their treatments. Knowledge on cytogenetics and molecular biology has an important impact on the determination of the prognosis and the appropriate treatment scheme. In Venezuela there is limited knowledge regarding the molecular genetics of this onco-hematological alteration. The aim of this work was to evaluate the most frequent genetic alterations in Venezuelan patients with a clinical diagnosis of acute lymphoblastic leukemia. A cross-sectional, descriptive and prospective study was carried out from 2006 to 2014, in which the translocations ETV6/RUNX1, MLL/AF4, TCF3/PBX1, BCR/ABL1, as well as mutations in the PAX5 and FLT3 genes were evaluated through the use of different types of PCR. One hundred and thirty patients with a clinical diagnosis of acute lymphocytic leukemia were included in the study. Molecular alterations were identified in 56 patients (43.1%), in which we observed the presence of one or several alterations in conjunction in the same patient. The alterations identified were t(12; 21) (11.5%), t(4; 11) (8.5%), t(1; 19) (10%), t(9; 22) (20.8%), ITD-FLT3 (14.8%), P80S mutation (4.2%) and S77del (4.2%) in the PAX5 gene. The prevalence of BCR/ABL is one of the highest described so far in cases of ALL where most of the population is made up of pediatric patients. These results represent the first molecular study of ALL in Venezuela, laying the foundations for the diagnosis and monitoring of the disease in its population.
ABSTRACT
Translocation between chromosomes 1 and 19 is well documented in ALL. Here, we report a case of refractory anemia with ring sideroblasts associated with marked thrombocytosis with der(19)t(1;19). A 67-yr-old man was admitted to our hospital with anemia and thrombocytosis. The aspirated bone marrow showed erythroid and megakaryocytic hyperplasia and dyspoiesis. Iron staining showed that the ring sideroblasts increased in number. Bone-marrow cell karyotyping showed 46,XY,der(19)t(1;19)(q23;p13)[9]/46,XY,del(5)(q21)[2]/46,XY[9]. PCR analysis showed the absence of the TCF3-PBX1 rearrangement. The patient was treated with hydroxyurea and intermittent blood transfusion. It is known that t(1;19)(q23;p13) leads to a TCF3-PBX1 fusion gene, whose product is a powerful transcriptional activator that plays a key role in the development of ALL. However, t(1;19) has rarely been reported in myeloid neoplasms and the TCF3-PBX1 fusion gene has not been detected. This implies that other genes might be involved in the TCF3-PBX1 rearrangement, or an alternative TCF3-PBX1 fusion transcript with a different breakpoint has not been detected to date. Further research and case studies, including the use of molecular analysis techniques, are required to evaluate the clinical and prognostic significance of t(1;19) in the development of myeloid neoplasms.