p190bcr/abl rearrangement in myelodysplastic syndromes: two reports and review of the literature

Philadelphia Translocation in MDS: A Case Report and a Brief Review of the Literature Looking at Its Prevalence, Disease Progression, and Treatment Options

Myelodysplastic syndrome (MDS) is a group of clonal disorders characterized by ineffective and dysplastic hematopoiesis in the bone marrow with variable risk of progression to leukemia. MDS is characterized by specific karyotypic and molecular abnormalities. The t(9 : 22) Philadelphia translocation is not a common abnormality found in MDS, and it is not included in the prognostic indices for germline mutations. There are no definitive treatment guidelines for these patients either. Here, we reviewed previously reported cases of MDS with the Philadelphia translocation with a goal to determine their prognosis and treatment options, specifically the tyrosine kinase inhibitors (TKIs).

Secondary Philadelphia chromosome acquired during therapy of acute leukemia and myelodysplastic syndrome

The Philadelphia chromosome resulting from t(9;22)(q34;q11.2) or its variants is a defining event in chronic myeloid leukemia. It is also observed in several types of de novo acute leukemia, commonly in B lymphoblastic leukemia, and rarely in acute myeloid leukemia, acute leukemia of ambiguous lineage, and T lymphoblastic leukemia. Acquisition of the Philadelphia chromosome during therapy of acute leukemia and myelodysplastic syndrome is rare. We reported 19 patients, including 11 men and 8 women with a median age of 53 years at initial diagnosis. The diagnoses at initial presentation were acute myeloid leukemia (n = 11), myelodysplastic syndrome (n = 5), B lymphoblastic leukemia (n = 2), and T lymphoblastic leukemia (n = 1); no cases carried the Philadelphia chromosome. The Philadelphia chromosome was detected subsequently at relapse, or at refractory stage of acute leukemia or myelodysplastic syndrome. Of 14 patients evaluated for the BCR-ABL1 transcript subtype, 12 had the e1a2 transcript. In 11 of 14 patients, the diseases before and after emergence of the Philadelphia chromosome were clonally related by karyotype or shared gene mutations. Of 15 patients with treatment information available, 7 received chemotherapy alone, 5 received chemotherapy plus tyrosine kinase inhibitors, 2 received tyrosine kinase inhibitors only, and 1 patient was not treated. Twelve patients had follow-up after acquisition of the Philadelphia chromosome; all had persistent/refractory acute leukemia. Thirteen of 15 patients died a median of 3 months after the emergence of the Philadelphia chromosome. In summary, secondary Philadelphia chromosome acquired during therapy is rare, and is associated with the e1a2 transcript subtype, terminal disease stage, and poor outcome.

Uncovering Clinical Features of De Novo Philadelphia Positive Myelodysplasia

Myelodysplastic syndrome (MDS) is cytogenetically heterogeneous and retains variable risk for acute myeloid leukemia transformation. Though not yet fully understood, there is an association between genetic abnormalities and defects in gene expression. The functional role for infrequent cytogenetic alteration remains unclear. An uncommon chromosomic abnormality is the presence of the Philadelphia (Ph) chromosome. Here, we report a patient with Ph+ MDS treated with low dose Dasatinib who achieved hematologic response for 7 months. In addition, we also examined the English literature on all de novo Ph + MDS cases between 1996 and 2015 to gain insight into clinical features and outcome.

BCR-ABL-positive acute myeloid leukemia: a new entity? Analysis of clinical and molecular features

BCR-ABL-positive acute myeloid leukemia (AML) is a rare subtype of AML that is now included as a provisional entity in the 2016 revised WHO classification of myeloid malignancies. Since a clear distinction between de novo BCR-ABL+ AML and chronic myeloid leukemia (CML) blast crisis is challenging in many cases, the existence of de novo BCR-ABL+ AML has been a matter of debate for a long time. However, there is increasing evidence suggesting that BCR-ABL+ AML is in fact a distinct subgroup of AML. In this study, we analyzed all published cases since 1975 as well as cases from our institution in order to present common clinical and molecular features of this rare disease. Our analysis shows that BCR-ABL predominantly occurs in AML-NOS, CBF leukemia, and AML with myelodysplasia-related changes. The most common BCR-ABL transcripts (p190 and p210) are nearly equally distributed. Based on the analysis of published data, we provide a clinical algorithm for the initial differential diagnosis of BCR-ABL+ AML. The prognosis of BCR-ABL+ AML seems to depend on the cytogenetic and/or molecular background rather than on BCR-ABL itself. A therapy with tyrosine kinase inhibitors (TKIs) such as imatinib, dasatinib, or nilotinib is reasonable, but-due to a lack of systematic clinical data-their use cannot be routinely recommended in first-line therapy. Beyond first-line treatment of AML, the use of TKI remains an individual decision, both in combination with intensive chemotherapy and/or as a bridge to allogeneic stem cell transplantation. In each single case, potential benefits have to be weighed against potential risks.

Late-appearing Philadelphia chromosome in childhood acute myeloid leukemia

A 3-year-old female was diagnosed with acute myeloid leukemia (AML-M2). The disease was refractory to various chemotherapeutic agents. Cytogenetic analysis revealed a clone with trisomy 8 at diagnosis that was replaced by a clone containing a t(11;15) and del(20q) by the end of the second induction. A new clone, characterized by a Philadelphia chromosome, with the minor BCR/ABL p190 transcript, emerged 14 months after diagnosis and remained to the end of disease course. The late occurrence of the Philadelphia chromosome in AML has been documented rarely in adults.

Haunting appearance of bcr/abl fusion gene products in a patient with therapy related leukaemia

A 81-year-old man was diagnosed as multiple myeloma and had received melphalan for 6 years. After that, he developed acute myeloid leukemia (AML) with monosomy 7 and minor bcr/abl transcripts. Fluorescence in situ hybridization identified no detectable level of bcr/abl rearrangement. During chemotherapy for AML, minor bcr/abl transcripts disappeared and instead major bcr/abl transcripts emerged. He died of pneumonia 3 months later. At that time, neither minor nor major bcr/abl transcripts were seen. These observations suggest that certain therapy related leukemia may be susceptible to generate very small clones with bcr/abl rearrangements.

Philadelphia chromosome positive myelodysplastic syndrome and acute myeloid leukemia—retrospective study and review of literature

We conducted a retrospective study to define the significance of Philadelphia chromosome (Ph) in myelodysplastic syndrome and acute leukemia in the adults at this institution and the literature was reviewed. One hundred forty-eight cases of t(9;22)(q34;q11) were identified for the period September 1993 through August 2001. The presentation of 124 cases (84%) was that of typical CML in chronic phase. Nineteen cases (13%) presented as de novo ALL, two cases (1%) presented as de novo AML and three cases (2%) presented as myelodysplastic syndrome (MDS). The estimated incidences of t(9;22)(q34;q11) in ALL and AML are 21 and 0.6%, respectively. Ph+ AMLs are increasingly being reported with either M-BCR or m-BCR gene rearrangements, similar to those found with Ph+ ALL lending support to the notion that Ph+ AMLs are distinct entities and not merely blastic phases of undiagnosed CML. This is further supported by the existence of Ph+ MDS cases.

Myelodysplastic syndrome in childhood: report of two cases with deletion of chromosome 4 and the Philadelphia chromosome

We report two pediatric patients with unclassified myelodysplastic syndrome (MDS) by the French-American-British (FAB) group. Both cases had clinical and hematological peculiarities, which had not been described yet. The cytogenetic alterations were 4q deletion and the Philadelphia (Ph) chromosome which appeared at different moments of the disease. One patient showed the Ph chromosome at disease transformation and the other at diagnosis. The different breakpoints at 4q and the presence of Ph could be a marker of this form of MDS. The association of clinical and hematological findings suggests the possibility of a new group of pediatric MDS.

A variant form of myelodysplastic syndrome with Ph- minor-BCR/ABL transcript

This study concerns a patient with minor (m)-BCR/ABL transcript-positive and Philadelphia (Ph) chromosome-negative myelodysplastic syndrome (MDS). The patient was a 78-year-old man whose condition was diagnosed as refractory anemia with excess of blasts in transformation. Molecular genetic studies, using reverse transcriptase polymerase chain reaction analysis detected m-BCR/ABL messenger RNA. We used spectral karyotyping to analyze metaphase cells but could not detect a Ph chromosome. Fluorescence in situ hybridization, however, revealed fusion signals of BCR and ABL probes on an apparently normal chromosome 22.

Molecular features of primary MDS with cytogenetic changes

Cytogenetic changes in primary myelodysplastic syndromes (MDS) have been extremely useful to identify clonality and to define specific clinico-pathological entities. More recently, with the development of DNA technology, a bulk of new information has been added to classical cytogenetics. Genes corresponding to chromosomal breakpoints implicated in reciprocal translocations have been cloned. Search for the minimal lost region has been the aim of the so-called deletion mapping approach to pick up the hypothetical suppressor gene(s) critical for typical deletions of MDS. Correlation has been found between gene mutations, deletions, expression, and clinical-hematological or cytogenetic features of MDS. Integration of fluorescence in situ hybridization at DNA level and of immunophenotyping at cellular level is an elegant tool to investigate clonal affiliation in MDS with distinct genetic changes.