María Fernanda Palacios

Interphase cytogenetic analysis in Argentinean B-cell chronic lymphocytic leukemia patients: association of trisomy 12 and del(13q14)

We have evaluated genomic aberrations by conventional cytogenetics and fluorescence in situ hybridization (FISH) analysis in a series of 57 Argentinean B-cell chronic lymphocytic leukemia (B-CLL) patients. The studies were performed on stimulated peripheral blood lymphocytes. FISH analysis for trisomy 12, 13q14 deletion, and monosomy of TP53 (also known as p53) was performed according to standard protocols. Our results showed 46.3% of patients with clonal chromosomal alterations by conventional cytogenetics and 80.7% by FISH. Trisomy 12 was found in 21.9% of patients by G-banding analysis and in 35% by FISH studies. Allelic loss of 13q14 was observed in 63.2% patients, most of them showing D13S319 and D13S25 deletion; 11% of patients showed TP53 monosomy. Coexistence of trisomy 12 and 13q14 deletion was found in 17.5% of patients. In this group, deletion 13q14 was the prevalent clone, with percentages 25-35% higher than those observed for trisomy 12, suggesting clonal evolution. The coexistence of trisomy 12 with deletion 13q14 was observed in a higher frequency than reported in the literature. A probable adverse prognosis is suggested for this group of patients, likely related to clonal evolution.

Promyelocytic Blast Crisis of Chronic Myelogenous Leukaemia with Translocations (9;22) and (15; 17)

The promyelocytic blast crisis is a rare form of transformation during the evolution of chronic myeloid leukaemia (CML). We report a case of promyelocytic blast crisis with t(15;17) in addition to t(9;22). The morphology and immunophenotype of the blasts were similar to those seen in acute promyelocytic leukaemia (APL). The t(15;17) was confirmed by FISH. The patient had evidence of coagulopathy with clinical and laboratory findings of disseminated intravascular coagulation (DIC). This report highlights the importance of correlating the results of multiple diagnostic methods in order to establish a correct diagnosis of the promyelocytic blast crisis of CML.

Cytogenetic, FISH, and molecular studies in a case of B‐cell chronic lymphocytic leukemia with karyotypic evolution

Abstract:  We report the clinical, cytogenetic, fluorescence in situ hybridization (FISH) and molecular findings in a 54‐yr‐old male patient diagnosed with B‐cell chronic lymphocytic leukemia (B‐CLL), who showed progression to a diffuse large B‐cell lymphoma (Richters syndrome). Genetic studies were performed at diagnosis and during the Richters transformation (RT). A clonal karyotype with two dicentric chromosomes, psu dic(12,21)(q24;q10) and dic(17,18)(p11.2;p11.2), was found. Both rearrangements were confirmed by FISH. Molecular cytogenetics analysis using p53 probe showed monoallelic loss of this tumor suppressor gene in 43.8% and 77.3% of cells for the first and the second studies, respectively). In both studies, deletions of D13S319 (18% and 12% of cells) and D13S25 loci (13% and 12% of cells) at 13q14 were found. Polymerase chain reaction analysis showed the MBR/JH rearrangement of the bcl‐2 gene. FISH studies using LSI bcl‐2/IgH probe allowed quantifying the clonal cell population with this rearrangement (4% and 6.6% of cells at diagnosis and RT, respectively). To our knowledge, this is the first case with a psu dic(12,21) described in B‐CLL. The low percentage of cells with the 13q14 deletion and bcl‐2/IgH rearrangement suggests that they were secondary events that resulted from clonal evolution. Our patient had a short survival (9 months) and a clear lack of response to several therapeutic agents, confirming the association of p53 gene deletion and karyotypic evolution with disease progression.

dup(12)(q13–q22) and 13q14 Deletion in a Case of B-Cell Chronic Lymphocytic Leukemia

Cases with partial trisomy 12 have rarely been found in B-cell chronic lymphocytic leukemia (CLL). We report our clinical, cytogenetic and fluorescence in situ hybridization (FISH) findings in a CLL patient with a duplication of part of the long arm of chromosome 12 between bands q13–q22. This patient was the only case with this duplication among the 112 cases (0.9%) of CLL cytogenetically analyzed in our laboratory. FISH studies using unique-sequence specific probes for the RB-1 (retinoblastoma) gene and the D13S319 locus at the 13q14 band showed a monoallelic loss for the D13S319 locus (20% of cells) with a diploid RB-1 gene. Our case showed an atypical morphology (35% prolymphocytes), a high proliferation rate and progression of the disease, indicating that the duplication of this region may be equivalent to complete trisomy 12 in CLL patients.

Trilineage Phenotypic Compromise in Acute Leukemia

The expression of three lineage specific antigens in the leukemic blasts is extremely infrequent. We here report a case of triphenotypic acute leukemia with involvement of the myeloid and B and T lineages. The morphology of the blasts showed promyelocytic features with agranular cytoplasm, suggesting a M3-variant of AML. The blasts were positive for myeloperoxidase PAS and Sudan Black. Immunophenotype and cytogenetics did not confirm M3-AML diagnosis, showing a trilineage compromise (myeloid and T and B lymphoid markers) and the cytogenetic alterations +8 and +11, respectively. This report highlights the importance of correlating the results of multiple diagnostic methods in order to establish a correct diagnosis of mixed lineage acute leukemias, and allows evaluation of the prognostic importance of this subgroup of patients.

Soluble RANKL production by leukemic cells in a case of chronic lymphocytic leukemia with bone destruction

Fil: Borge, Mercedes. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina

CD8 Expression in a Case of Chronic Lymphocytic Leukemia with Trisomy 12

We report a case of B-cell chronic lymphocytic leukemia (B-CLL) with aberrant expression of the T-cell-associated antigen CD8, as revealed by two-color flow-cytometric analysis. DNA studies showed immunoglobulin heavy-chain gene rearrangement, but not of γ-chain T-cell receptor, confirming the B-cell origin of the neoplastic cells. Ploidy analysis showed a tetraploid population and high S-phase fraction. B-CLL cells also carried trisomy 12, detected by fluorescence in situ hybridization. The identification of more cases with the same features would be necessary to establish the prognosis of this subtype of B-CLL.