Distribution of BCR::ABL1 Transcripts in the Different Clinical Phases of Chronic Myeloid Leukemia: Effect on Hematological Parameters and Patient Survival.

Chronic myeloid leukemia (CML) is a hematopoietic stem cell disorder characterized by the presence of the Philadelphia chromosome, a product of the reciprocal translocation t(9;22)(q34;q11), in the BCR and ABL genes. These rearrangements in both genes lead to the formation of various fusion mRNA products, with preferential expression of b2a2, b3a2, and other BCR::ABL1 mRNA variants, combined with additional chromosomal abnormalities. Notably, the distribution and frequency of different mRNA variants vary in different populations. However, studies concerning this in Mexico are limited, and the results have been inconclusive. This study therefore aimed to determine the distribution of BCR::ABL1 mRNA variants in different clinical phases of CML and their effect on hematological parameters and patient survival. This study included 33 patients, whose demographic, clinical, and molecular data on BCR::ABL1 mRNA variants and hematological parameters were collected to identify potential associations. A total of 84.8% (n = 28) of patients had BCR::ABL1 translocation and increased platelet and basophil counts. The most frequent mRNA variant was b3a2 (64.3%), followed by b2a2 (28.6%) and e1a2 (3.6%). Concerning the clinical phases of CML, 75.8% (n = 25), 21.2% (n = 7), and 3% (n = 1) of patients were in the chronic, blast, and accelerated phases, respectively. Moreover, the b3a2 mRNA variant was more commonly identified in patients in the chronic phase. No correlation was observed between mRNA variant expression and patient survival. However, b2a2 was indicative of patients with longer survival as well as those treated with imatinib or nilotinib. Additionally, platelet count could be a marker of BCR::ABL1 translocation.

Clinical efficacy and safety of flumatinib versus dasatinib combined with multi-drug chemotherapy in adults with Philadelphia-positive acute lymphoblastic leukemia.

INTRODUCTION: Flumatinib, a highly selective ABL kinase inhibitor, exhibits stronger inhibition of intracellular BCR-ABL tyrosine kinase activity, compared to Imatinib. However, there is limited research comparing the real-world efficacy and safety of flumatinib and dasatinib in patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL). OBJECTIVE: Investigating the differences in therapeutic efficacy and safety between flumatinib and dasatinib in combination with multi-drug chemotherapy for the treatment of newly diagnosed Ph+ ALL. METHOD: In this study, we assessed 43 patients with newly diagnosed Ph+ ALL (20 in the flumatinib group, 23 in the dasatinib group). RESULTS: There were no significant differences in gender, age, fusion gene type, initial blood routine, bone marrow blast cell ratio or chromosome karyotype between the two groups. Within 1 month, there were no significant differences in the complete response (CR), major molecular response (MMR) or minimal residual disease (MRD) negativity rate between the flumatinib and dasatinib groups. Similarly, within 3 months, there were no significant differences in CR or MMR rates between the two groups. However, the rates of complete molecular response (CMR) and MRD negativity within 3 months were significantly higher in the flumatinib group, compared to the dasatinib group (P < 0.05). Additionally, the flumatinib group exhibited fewer adverse reactions compared to the dasatinib group. CONCLUSION: These findings suggest that flumatinib is a safe and effective tyrosine kinase inhibitor (TKI) for achieving CMR and MRD negativity in patients with Ph+ ALL, as supported by this small series of patients.

Quantitative detection of T315I mutations of BCR::ABL1 using digital droplet polymerase chain reaction.

BACKGROUND: T315I mutations of the BCR::ABL1 gene lead to resistance to tyrosine kinase inhibitors (TKIs). This study evaluated the performance of digital droplet polymerase chain reaction (ddPCR) in quantifying T315I mutations and their frequency in Philadelphia chromosome (Ph) positive hematological patients. METHODS: The course of disease and BCR::ABL1 fusion transcripts (e13a2, e14a2 and e1a2) were retrospectively reviewed in 21 patients with acute lymphoblastic leukemia (ALL) and 85 patients with chronic myeloid leukemia (CML). T315I mutation analysis was carried out using ddPCR and the limit of detection was assessed using mutant T315I DNA at varying variant allele fractions. RESULTS: T315I mutations were found in two ALL patients and one CML patient without remission in molecular biology and with mutation burdens of 29.20%, 40.85%, and 3.00%, respectively. The mutation burden of ALL patients was higher than that of CML patients, but there was no significant difference between the two (p-value = 0.0536). The test's limit of detection was 0.02% with a correlation coefficient greater than 0.99 between the expected and actual detection abundances. CONCLUSION: T315I mutations have a high incidence in Ph-positive ALL patients even if the course of disease is short. In molecular biology, T315I mutation detection is indicated for CML patients not in remission.

How to Manage Philadelphia-Positive Acute Lymphoblastic Leukemia in Resource-Constrained Settings.

Recent studies have indicated that more than half of adult patients newly diagnosed with Ph+ ALL can now achieve a cure. However, determining the most suitable protocol for less-resourced settings can be challenging. In these situations, we must consider the potential for treatment toxicity and limited access to newer agents and alloSCT facilities. Currently, it is advisable to use less intensive induction regimens for Ph+ ALL. These regimens can achieve high rates of complete remission while causing fewer induction deaths. For consolidation therapy, chemotherapy should remain relatively intensive, with careful monitoring of the BCR-ABL1 molecular transcript and minimal residual disease. AlloSCT may be considered, especially for patients who do not achieve complete molecular remission or have high-risk genetic abnormalities, such as IKZF1-plus. If there is a loss of molecular response, it is essential to screen patients for ABL mutations and, ideally, change the TKI therapy. The T315I mutation is the most common mechanism for disease resistance, being targetable to ponatinib. Blinatumomab, a bispecific antibody, has shown significant synergy with TKIs in treating this disease. It serves as an excellent salvage therapy, aside from achieving outstanding results when incorporated into the frontline.

An interesting case of chronic myeloid leukemia with twists and turns.

Additional cytogenetic abnormalities (ACA) are known to crop up in Ph+ cells of chronic myeloid leukemia (CML) patients due to cytogenetic evolution. But the frequency of molecular evolution and ACA is much less in Ph- cells of CML patients and is poorly understood. We report an interesting and rare case of Ph+ CML, who progressed to B lymphoblastic crisis, achieved remission, and later developed Ph- acute myeloid leukemia (AML) with KMT2A gene rearrangement and no detectable BCR- ABL transcripts.

¿Es importante conocer el tipo de transcripto BCR-ABL en la leucemia mieloide crónica? / Is it important to know the type of BCR-ABL transcript in chronic myeloid leukemia?

La leucemia mieloide crónica se caracteriza por la ocurrencia de una translocación recíproca entre los cromosomas 9 y 22; que da origen a un cromosoma 22 derivativo conocido como Filadelfia. En el sitio de unión se forma el gen de fusión BCR-ABL que conlleva a la síntesis de una proteína híbridacon propiedades oncogénicas. El sitio de unión entre los cromosomas 9 y 22 es variable y da lugar a transcritos diferentes; los conocidos como e13a2 y e14a2 son los más frecuentes y estudiados. El análisis de las características clínico-hematológicas de presentación y la respuesta al tratamiento entre los pacientes portadores de e13a2 o e14a2 ha revelado diferencias que pueden ser útiles para la predicción del pronóstico. Se realizó una revisión de la literatura científica a través de PUBMED. Se analizó y resumió la información. Se evidencian diferentes características de presentación, pero no existe coincidencia entre todos los autores. Respecto al comportamiento de la respuesta al tratamiento con inhibidores de tirosina quinasa, algunos autores encuentran diferencias y algunos sugieren que puede tratarse de dos enfermedades diferentes. Puede ser importante conocer el tipo de transcripto BCR-ABL en la LMC ya que, al menos entre los dos más frecuentes, existen diferencias que pueden ser útiles en la predicción del pronóstico para el paciente, así como para el manejo del tratamiento(AU)

Chronic myeloid leukemia is characterized by the occurrence of a reciprocal translocation between chromosomes 9 and 22; which gives rise to a derivative chromosome 22 known as Philadelphia. At the binding site, the BCR-ABL fusion gene is formed, which leads to the synthesis of a hybrid protein with oncogenic properties. The binding site between chromosomes 9 and 22 is variable and gives rise to different transcripts; those known as e13a2 and e14a2 are the most frequent and studied. The analysis of the clinical-hematological characteristics of presentation and the response to treatment among patients with e13a2 or e14a2 has revealed differences that may be useful for the prediction of prognosis. To describe the different characteristics reported for one or another transcript and to know if it is important to know the type of transcript in the CML. A review of the scientific literature was carried out through PUBMED. The information was analyzed and summarized. Different presentation characteristics are evident but there is no coincidence between all the authors. Regarding the behavior of the response to treatment with tyrosine kinase inhibitors, some authors find differences and some suggest that it may be two different entities. It may be important to know the type of BCR-ABL transcript in CML cause, at least between the two most frequent, there are differences that may be useful in predicting the prognosis for the patient as well as for the management of treatment(AU)

Chronic Myelogenous Leukemia with Double Philadelphia Chromosome and Coexpression of p210 and p190 Fusion Transcripts.

The Philadelphia (Ph+) chromosome, t(9;22)(q34;q11.2), originates from a chimeric gene called BCR-ABL and is present in more than 90% of CML patients. Most patients with CML express the protein p210 BCR-ABL and, with a frequency lower than 5%, express rare isoforms, the main one being p190. In the transition from the chronic phase to the blast phase (BP), additional chromosomal abnormalities, such as the presence of the double Ph+ chromosome, are revealed. Of the 1132 patients analyzed via molecular biology in this study, two patients (0.17%) showed the co-expression of the p210 and p190 isoforms for the BCR-ABL transcript, with the concomitant presence of a double Ph+ chromosome, which was observed via conventional cytogenetics and confirmed by fluorescent in situ hybridization. The BCR-ABL/ABL% p210 and p190 ratio increased in these two patients from diagnosis to progression to blast crisis. To our knowledge, this is the first report in the literature of patients who co-expressed the two main BCR-ABL transcript isoforms and concomitantly presented Ph+ chromosome duplication. The evolution from the chronic phase to BP often occurs within 5 to 7 years, and, in this study, the evolution to BP was earlier, since disease-free survival was on average 4.5 months and overall survival was on average 9.5 months. The presence of the p190 transcript and the double Ph+ chromosome in CML may be related to the vertiginous progression of the disease.

Respuesta molecular profunda con ponatinib en leucemia mieloide crónica en fase crónica con resistencia a imatinib y dasatinib: Reporte de caso y revisión de la literatura / Profound molecular response with ponatinib in chronic phase of chronic myeloid leukemia with resistance to imatinib and dasatinib: Case report and review of the literature

RESUMEN Se reporta el caso de una mujer quien a la edad de 54 años fue diagnosticada de leucemia mieloide crónica en fase crónica; inició tratamiento con inhibidor de tirosina cinasa de primera generación, y evidenció falla por ausencia de respuesta hematológica y citogenética. A pesar del cambio de tratamiento a un inhibidor de tirosina cinasa de segunda generación (dasatinib), no fue posible alcanzar niveles óptimos de respuesta, documentándose la positividad para la mutación T315I en dominio ABL de la tirosina cinasa desregulada BCR/ABL, frente a la cual el único medicamento que muestra actividad es ponatinib. Luego de iniciar tratamiento con ponatinib, se evidenciaron niveles óptimos de respuesta citogenética y molecular, así como una adecuada calidad de vida de la paciente.

SUMMARY We report the case of a woman who at the age of 54 years was diagnosed with chronic myeloid leukemia in chronic phase; she began treatment with a first-generation tyrosine kinase inhibitor, and evidenced failure due to the absence of a hematological and cytogenetic response. Despite changing treatment to a second-generation tyrosine kinase inhibitor (dasatinib), it was not possible to achieve optimal levels of response, documenting positivity for the T315I mutation in the ABL domain of the deregulated BCR/ABL tyrosine kinase, compared to ponatinib, the only drug that shows activity. After starting treatment with ponatinib, optimal levels of cytogenetic and molecular response were evidenced, as well as an adequate quality of life for the patient.

Adult acute lymphoblastic leukemia in a resource-constrained setting: outcomes after expansion of genetic evaluation.

Acute lymphoblastic leukemia (ALL) is a challenging disease with a growing genetic landscape, even though there is substantial gap between developed and non-developed countries when it comes to availability of such new technologies. This manuscript reports a 5-year retrospective cohort of newly diagnosed ALL patients and their genetic findings and outcomes. An expanded genetic evaluation by using FISH and RT-PCR was implemented, aiming to identify Ph-like alterations. Patients were treated according to our local protocol, which allocated patients according to age and Philadelphia-chromosome status. A total of 104 patients was included, with median age of 37.5 years. Philadelphia chromosome was detected in 33 cases of B-lineage. Among 45 Ph-negative B-lineage, after excluding KMT2A or TCF3-PBX1 cases, we identified 9 cases with Ph-like fusion. Ph-positive and Ph-like patients had higher initial WBC (p = 0.06). Out of 104 cases, two cases did not start chemotherapy and an early death rate of 10.8% was found. Allogeneic transplantation was performed in 18 cases, being ten performed in first CR. Three-year overall survival (OS) and 3-year event-free survival were 42.8% and 30.8%, respectively. For patients treated with a pediatric regimen, 3-year OS was 52.5%. Extramedullary disease (HR 0.42) and platelet counts (HR 0.9) were independently associated with OS. We still face excessive non-relapse mortality that compromises our results. Alternative strategies implementing FISH and RT-PCR are feasible and able to identify Ph-like fusions. Delays in allogeneic transplantation, as well as the unavailability of new agents, impact long-term survival. Measures to decrease early infection are desirable.

Quimioterapia intensiva asociada a imatinib en leucemia linfoblástica aguda del adulto, Philadelphia positivo. Experiencia en un hospital público / Intensive chemotherapy with tyrosine kinase inhibitors in philadelphia-positive acute lymphoblastic leukemia

Background: Before the advent of tyrosine kinase inhibitors (TKIs), patients with Philadelphia-positive Acute Lymphoblastic Leukemia (Ph+ALL) had a poor prognosis. The association of TKIs to intensive chemotherapy (CT) improved outcome. Aim: To evaluate results of an intensive CT protocol including TKI in a public hospital in Santiago, Chile. Material and Methods: All patients with Ph+ALL diagnosed between January 2010 and February 2019, and who met inclusion criteria for intensive CT, received the Ph+ALL national protocol in association with imatinib and were included in this analysis. Results: Thirty-five patients aged 15 to 59 years received treatment. Complete response (CR) was obtained in 97%. Measurable residual disease (MRD) was negative in 61% (19/31 evaluable cases) during follow-up, and 55% (16/29) were MRD (-) before three months. Relapse was observed in 13 cases. Three patients underwent allogeneic hematopoietic stem cell transplant (HSCT), two in CR1. The overall survival (OS) and event-free survival (EFS) at three years were 52 and 34%, respectively. In patients who achieved MRD negativity before three months, no statistically significant differences in OS (64 and 42% respectively, p = 0.15) or EFS (35 and 32% respectively, p = 0.37) were observed. Conclusions: The prognosis of Ph+ALL improved with the association of imatinib to intensive CT. MRD-negative status before three months in this series was not significantly associated with better outcomes. Our series suggests that the Ph+ALL national protocol associated to TKI is a therapeutic alternative with high CR and aceptable MRD (-) rates.

Philadelphia-positive B-lymphoblastic leukemia in a middle-income country - A real-world multicenter cohort.

Outside of clinical trials, few studies have addressed the outcomes of Ph+ acute lymphoblastic leukemia (ALL) in adults, especially from developing world. In this study, we conducted a multicenter analysis on the outcomes of patients aged > 15 years with Ph+ ALL, aiming to get to know an overview of the Brazilian experience as well as to explore baseline factors associated with relapse and mortality in our setting. Over these 10 years, patients were treated with diverse protocols, all of them always combined with a frontline tyrosine-kinase inhibitor. A total of 123 Ph+ ALL patients was included. Imatinib was the first line TKI in 97 %. The complete response rate was 79 %. The early death rate was 15 %, being associated with increasing age at diagnosis (p = 0.06). The use of intensive versus attenuated induction regimen was not associated with higher induction mortality (p = 0.99). Overall, 29 % of patients aged ≤ 60 years underwent allogeneic transplantation, 87 % in first CR. 4-year overall survival (OS) and relapse-free survival were 25 % and 24 %, respectively. The incidence of relapse (death as a competitor) was 29 %, while the non-relapse mortality was 42 %. Only age was independently associated with OS, and lactate dehydrogenase level and central nervous disease at diagnosis were related to relapse in our cohort. This is the first historical cohort multicenter study on Ph+ ALL from Brazil. Reporting these outcomes is essential to encourage public policies to expand access to new drugs and transplantation in middle-income countries.

Chronic myeloid leukemia-from the Philadelphia chromosome to specific target drugs: A literature review.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm and was the first neoplastic disease associated with a well-defined genotypic anomaly - the presence of the Philadelphia chromosome. The advances in cytogenetic and molecular assays are of great importance to the diagnosis, prognosis, treatment, and monitoring of CML. The discovery of the breakpoint cluster region (BCR)-Abelson murine leukemia (ABL) 1 fusion oncogene has revolutionized the treatment of CML patients by allowing the development of targeted drugs that inhibit the tyrosine kinase activity of the BCR-ABL oncoprotein. Tyrosine kinase inhibitors (known as TKIs) are the standard therapy for CML and greatly increase the survival rates, despite adverse effects and the odds of residual disease after discontinuation of treatment. As therapeutic alternatives, the subsequent TKIs lead to faster and deeper molecular remissions; however, with the emergence of resistance to these drugs, immunotherapy appears as an alternative, which may have a cure potential in these patients. Against this background, this article aims at providing an overview on CML clinical management and a summary on the main targeted drugs available in that context.

Comparison of microRNA Expression Profile in Chronic Myeloid Leukemia Patients Newly Diagnosed and Treated by Allogeneic Hematopoietic Stem Cell Transplantation.

Chronic myeloid leukemia (CML) results from a translocation between chromosomes 9 and 22, which generates the Philadelphia chromosome. This forms BCR/ABL1, an active tyrosine kinase protein that promotes cell growth and replication. Despite great progress in CML treatment in the form of tyrosine kinase inhibitors, allogeneic-hematopoietic stem cell transplantation (allo-HSCT) is currently used as an important treatment alternative for patients resistant to these inhibitors. Studies have shown that unregulated expression of microRNAs, which act as oncogenes or tumor suppressors, is associated with human cancers. This contributes to tumor formation and development by stimulating proliferation, angiogenesis, and invasion. Research has demonstrated the potential of microRNAs as biomarkers for cancer diagnosis, prognosis, and therapeutic targets. In the present study, we compared the circulating microRNA expression profiles of 14 newly diagnosed patients with chronic phase-CML and 14 Philadelphia chromosome-negative patients after allo-HSCT. For each patient, we tested 758 microRNAs by reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis. The global expression profile of microRNAs revealed 16 upregulated and 30 downregulated microRNAs. Target genes were analyzed, and key pathways were extracted and compared. Bioinformatics tools were used to analyze data. Among the downregulated miRNA target genes, some genes related to cell proliferation pathways were identified. These results reveal the comprehensive microRNA profile of CML patients and the main pathways related to the target genes of these miRNAs in cytogenetic remission after allo-HSCT. These results provide new resources for exploring stem cell transplantation-based CML treatment strategies.

Prognostic significance of a normal karyotype in adult patients with BCR-ABL1-positive acute lymphoblastic leukemia in the tyrosine kinase inhibitor era

OBJECTIVE: The occurrence of cryptic Philadelphia (Ph) chromosome translocation is rare in BCR-ABL1-positive acute lymphoblastic leukemia (BCR-ABL1+ ALL) and is of unknown significance in the tyrosine kinase inhibitor (TKI) era. METHODS: We retrospectively studied a series of adult patients receiving TKI-based therapy to evaluate the prognostic impact of the normal karyotype (NK) (n=22) in BCR-ABL1+ ALL by comparison with the isolated Ph+ karyotype (n=54). RESULTS: There were no statistically significant differences in clinical characteristics and complete remission rate between the two groups. Compared with the isolated Ph+ group, the NK/BCR-ABL1+ group had a higher relapse rate (55.0% versus 29.4%, p=0.044). Overall survival (OS) and disease-free survival (DFS) were significantly shorter in the NK/BCR-ABL1+ group than in the isolated Ph+ group [median OS: 24.5 versus 48.6 (months), p=0.013; median DFS: 11.0 (months) versus undefined, p=0.008]. The five-year OS and DFS for patients with NK/BCR-ABL1+ were 19.2% and 14.5%, respectively; those for patients with isolated Ph+ were 49.5% and 55.7%, respectively. Thirty-four (44.7%) patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in this study. Among the patients who received allo-HSCT, the median OS and DFS in the NK/BCR-ABL+ group (n=9) were 35.5 and 27.5 months, respectively, while those in the isolated Ph+ group (n=25) were undefined. There was a trend of significant statistical difference in the OS between the two subgroups (p=0.066), but no significant difference in the DFS. Multivariate analysis revealed that NK was independently associated with worse OS and DFS in BCR-ABL1+ ALL patients [Hazard ratio (HR) 2.256 (95% confidence interval (CI), 1.005-5.066), p=0.049; HR 2.711 (95% CI, 1.319-5.573), p=0.007]. CONCLUSION: Our results suggest that the sub-classification of an NK could be applied in the prognostic assessments of BCR-ABL1+ ALL. In addition, allo-HSCT should be actively performed to improve prognosis in these patients.

Isocromosoma Filadelfia en dos pacientes con leucemia mieloide crónica / Philadelphia isochromosome in two patients with chronic myeloid leukemia

RESUMEN El cromosoma Filadelfia (Ph por su abreviatura del inglés "Philadelphia") se presenta en más del 90 % de los pacientes con leucemia mieloide crónica. Un cromosoma Ph extra es una de las alteraciones secundarias comúnmente observada como evolución clonal de la enfermedad y se puede presentar como un derivativo adicional o un isocromosoma del 22 derivativo. Es una alteración adquirida durante la progresión de la enfermedad con implicación pronóstica. Se presentan dos casos con diagnóstico de leucemia mieloide crónica, resistentes al tratamiento con mesilato de imatinib. En el estudio cromosómico con técnica de banda G se observaron en ambos pacientes líneas celulares con dos isocromosomas del derivativo del 22, 2ider (22) t (9; 22). El primer caso falleció en crisis blástica y el segundo luego de no responder al tratamiento de primera línea, se le indicó nilotinib pero su evolución fue no satisfactoria. Las alteraciones cromosómicas secundarias están asociadas con un impacto negativo en la supervivencia y progresión a fase acelerada y crisis blástica de la enfermedad.

ABSTRACT The Philadelphia chromosome (Ph) is present in more than 90% of patients with chronic myeloid leukemia. An extra Ph chromosome is one of the secondary alterations commonly observed in clonal evolution and it could be as na additional derivative or anisochromosome of the derivative. It is na alteration acquired during the progression of the disease with prognostic implications. We present two cases with a diagnosis of chronic myeloid leukemia, Who showed resistance to treatment with imatinib mesylate. In both patients,the chromosomal study with G-band technique, show cell lines with two isochromosomes from the derivative of 22, 2ider(22)t(9; 22). The first case died in blast crisis and to the second after not responding to the first line treatment, was precribed nilotinib but the evolution was unsatisfactory. Secondary chromosomal alterations are associated with a negative impact on survival and the progression to accelerated phase and blast crisis of the disease.

Circulating microRNAs expression profile in newly diagnosed and imatinib treated chronic phase - chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is a stem cell derived malignant disorder result of translocation t(9;22)(q34;q11) called Philadelphia chromosome (Ph+). microRNAS (miRNAs) are involved in several biological processes, altering the progression of various pathologies, including CML. This study evaluated whether circulating miRNAs display differential expression profiles in peripheral blood of CML-Chronic Phase (CML-CP) patients newly diagnosed in comparison with CML-CP treated with imatinib. We obtained peripheral blood samples from CML-CP Ph+ patients divided among group 1 (untreated newly diagnosed) and group 2 (treated with imatinib). A pool of total leukocytes from healthy donors was considered as control group. Expression analyses were performed for 768 miRNAs by RT-qPCR array. Bioinformatic tools were used to identify significant pathways and interaction networks. We found 80 deregulated miRNAs between the groups and, according to bioinformatic analysis, they are involved in different pathways, including molecular mechanisms of cancer. The study allows better understanding of disease molecular behavior, and it is useful for possible monitoring CML treatment and prognostic biomarkers identification.

The role of cytogenetics and molecular biology in the diagnosis, treatment and monitoring of patients with chronic myeloid leukemia / O papel da citogenética e da biologia molecular no diagnóstico, no tratamento e no monitoramento de pacientes com leucemia mieloide crônica

ABSTRACT Chronic myeloid leukemia (CML) is the most common myeloproliferative disorder among chronic neoplasms. The history of this disease joins with the development of cytogenetic analysis techniques in human. CML was the first cancer to be associated with a recurrent chromosomal alteration, a reciprocal translocation between the long arms of chromosomes 9 and 22 - Philadelphia chromosome. This work is an updated review on CML, which highlights the importance of cytogenetics analysis in the continuous monitoring and therapeutic orientation of this disease. The search for scientific articles was carried out in the PubMed electronic database, using the descriptors "leukemia", "chronic myeloid leukemia", "treatment", "diagnosis", "karyotype" and "cytogenetics". Specialized books and websites were also included. Detailed cytogenetic and molecular monitoring can assist in choosing the most effective drug for each patient, optimizing the treatment. Cytogenetics plays a key role in the detection of chromosomal abnormalities associated with malignancies, as well as the characterization of new alterations that allow more research and increase knowledge about the genetic aspects of these diseases. The development of new drugs, through the understanding of the molecular mechanisms involved, will allow a possible improvement in the survival of these patients.

RESUMO Leucemia mieloide crônica (LMC) é a desordem mieloproliferativa mais comum entre as neoplasias crônicas. A história dessa doença se alia ao desenvolvimento de técnicas de análise citogenética em humanos. Foi o primeiro câncer a ser associado a uma alteração cromossômica recorrente, uma translocação recíproca entre os braços longos do cromossomo 9 e 22 - o cromossomo Philadelphia. Este trabalho é uma revisão atualizada sobre LMC, o qual destaca a importância da análise citogenética no monitoramento contínuo e na orientação terapêutica dessa doença. A pesquisa de artigos científicos foi realizada no banco de dados PubMed, usando os descritores "leucemia", "leucemia mieloide crônica", "tratamento", "diagnóstico", "cariótipo" e "citogenética". Livros e sites especializados também foram incluídos. O monitoramento citogenético e molecular detalhado pode auxiliar na escolha do medicamento mais efetivo para cada paciente, otimizando seu tratamento. A citogenética desempenha um papel fundamental na detecção de anormalidades cromossômicas associadas a malignidades, bem como na caracterização de novas alterações que permitem mais pesquisas e ampliação do conhecimento sobre os aspectos genéticos dessas doenças. O desenvolvimento de novas drogas, através da compreensão dos mecanismos moleculares envolvidos, permitirá uma possível melhora na sobrevida desses pacientes.

An unusual translocation, t(1;11)(q21;q23), in a case of chronic myeloid leukemia with a cryptic Philadelphia chromosome.

Chronic myeloid leukemia (CML) is characterized by the translocation t(9;22)(q34;q11) [Philadelphia (Ph) chromosome). Although not frequently occurring, additional chromosome abnormalities (ACAs) can be detected at diagnosis and a number have been associated with an adverse cytogenetic and molecular outcome. The present study reports a case of CML presenting with the translocation t(1;11)(q21;q23) and a cryptic Ph chromosome. The presence of ACAs could generate greater genetic instability, promoting the emergence of further alterations. The present findings suggest that t(1;11)(q21;q23) can prevent a good response to tyrosine kinase inhibitor (TKI) therapy developing a primary resistance. In the present patient, at a recent follow-up, the T315I mutation was detected. This mutation confers full resistance to all available TKI, except ponatinib, which was not a therapeutic option due to comorbidities.

Análisis de metilación en pacientes con leucemia mieloide crónica en diferentes instituciones médicas de Medellín / Methylation analysis in patients with chronic myeloid leukemia in different medical institutions in Medellín

Fundamento: la leucemia mieloide crónica es una neoplasia mieloproliferativa crónica que se caracteriza por la presencia del cromosoma filadelfia. Para esta se ha diseñado como tratamiento los inhibidores de tirosin kinasa, que genera en los pacientes una respuesta hematológica, citogenética y molecular. Esta enfermedad se caracteriza por presentar tres fases clínicas que son producto de la acumulación de daños tanto genéticos representados por mutaciones puntuales y alteraciones en el cariotipo; y cambios epigenéticos en genes tales como ABL-1, OSCP1, PDLIM4, NPM2, ER y p15. Objetivo: describir los patrones de metilación de seis genes en pacientes con leucemia mieloide crónica en distintas fases de la enfermedad tratados con algún ITK´s o en su defecto con hidroxiurea en dos hospitales de Medellín. Métodos: se realizó un estudio analítico trasversal, en el que se recolectaron 34 muestras a conveniencia de pacientes con leucemia mieloide crónica. Para hacer el análisis de estas muestras se usó una PCR específica de metilación. Los datos analizados no se distribuyeron de forma normal, por lo que se realizaron pruebas no paramétricas como U de Man Whitney y test exacto de Fischer, con una significancia de 0,05. Resultados: se encontró diferencias de estadísticas significativas en los datos del hemograma de ambas fases de la enfermedad, también se encontró una alta frecuencia de genes metilados en fase acelerada. La metilación de p15, ABL-1, ER son independiente de la fase de la enfermedad. En los pacientes tratados con hidroxiurea se observó una metilación del 100 % para los genes NPM2, OSCP1 y PDLIM4 este comportamiento no se observó en los individuos tratados con ITK´S, no obstante, para aquellos pacientes que desarrollaron resistencia a los ITK´s se observó un porcentaje de metilación mayor en los genes OSCP1, ABL-1 y PDLIM4. Conclusiones: la metilación en los genes PDLIM4 y OSCP1, puede asociarse con pronóstico desfavorable, ya que puede estar relacionado con la progresión de fase crónica a acelerada y el desarrollo de resistencia a los ITK´s.

Background: chronic myeloid leukemia (CML) is a chronic myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome. A specific treatment is designed as tyrosine kinase inhibitors (ITK's), which induces patients to have a hematologic, cytogenetic and molecular response. This disease is characterized by three clinical phases that result from the accumulation of genetic damage, both represented by point mutations and alterations in the karyotype; and epigenetic changes in genes such as ABL, OSCP1, PDLIM4, Npm2, ER and p15. Objective: to describe the schemes of six gens in patients with chronic myeloid leukemia in different stages of the disease and treated with some ITK in two hospitals in Medellín. Methods: a descriptive transversal study was conducted, in which 34 samples were collected at the convenience of patients with chronic myeloid leukemia (CML). To make the analysis of these samples methylation specific PCR was done. Results: statistical differences in blood count data from both phases of the disease was found, a high frequency of methylated genes in accelerated phase was also found. p15 methylation, ABL, ER are independent of the stage of the disease. In patients treated with hydroxyurea, methylation of 100 % for OSCP1 and PDLIM4 genes was observed and this behavior was not observed in individuals treated with ITK'S. In patients who developed resistance to ITK's however was observed a higher percentage of methylation in genes OSCP1 and PDLIM4. Conclusions: methylation in PDLIM4 and OSCP1 genes could be associated with poor prognosis possibly being associated with progression of chronic to accelerated phase and the development of resistance to ITK's.

Acute Leukemia Characteristics are Different Around the World: the Mexican Perspective.

BACKGROUND: The incidence of acute leukemia (AL) has increased. Its prognosis is variable and depends on several baseline characteristics with a highly heterogeneous presentation. In Mexico, large-scale descriptive studies have not yet been published; the objective of this study was to analyze the initial basic characteristics of patients diagnosed with AL in our population. PATIENTS AND METHODS: In this multicenter, retrospective study, 1018 patients ≥ 16 years of age and diagnosed with AL between 2009 and 2014, were included. We described age, gender, complete blood count, and AL subtype according to flow cytometry analysis. RESULTS: Acute lymphoblastic leukemia (ALL) was as common as acute myeloid leukemia (AML) (51% vs. 49%). The median age was 31 years. Only 9.6% of patients with ALL were positive for the Philadelphia chromosome. No gender differences were observed. The median age at presentation of AML was 43 years. Acute promyelocytic leukemia was the most frequent AML subtype (38.3%), with a median age of 37 years. CONCLUSION: ALL is equally as frequent as AML in patients ≥16 years of age. Philadelphia-positive prevalence is less frequent than that reported in literature. AML cases occur in a younger age in comparison with other countries. There is a higher rate of acute promyelocytic leukemia among our patients compared with other non-Latin American populations. This study is the largest ever performed in Mexico regarding descriptive AL data.