Complex karyotypic abnormalities including t(8;22) in a patient with chronic lymphocytic leukemia

The clinical significance of 8q24/MYC rearrangement in chronic lymphocytic leukemia

Chromosome 8q24/MYC rearrangement is associated with Burkitt lymphoma and some aggressive B-cell lymphomas, but is rare in chronic lymphocytic leukemia. We here report a cohort of 20 chronic lymphocytic leukemia patients with 8q24/MYC rearrangement, 3 detected at time of initial diagnosis and 17 acquired after a median interval of 48 months. At the time when 8q24/MYC arrangement was detected, 18 patients had B-symptoms, 17 had lymphadenopathy, and 17 had splenomegaly. Histologically, typical chronic lymphocytic leukemia morphology was seen in six patients, increased prolymphocytes in nine and Richter's transformation in five patients. Eighteen patients had karyotypic information available that showed t(8;v) in a complex karyotype in 12 patients and in a non-complex karyotype in 6 patients. Fluorescence in situ hybridization confirmed MYC rearrangement in 17/17 patients. All patients required therapy after 8q24/MYC rearrangement was detected. At last follow-up, five of six patients with a non-complex karyotype were alive after a median of 74 months (10~143 months) from the detection of 8q24/MYC rearrangement. In contrast, 10 of 12 patients with a complex karyotype died with a median survival of 5.5 months. We conclude that 8q24/MYC rearrangement in chronic lymphocytic leukemia is rare and often acquired during the course of disease. If it is presented in a complex karyotype, it is often associated with Richter's transformation, refractory to therapy and an aggressive clinical course; on the other hand, if it is present in a non-complex karyotype, patients often respond to risk-adapted therapies and achieve remission.

The basis and rational use of molecular genetic testing in mature B-cell lymphomas

An increasing number of neoplasms are associated with variably specific genetic abnormalities. This is best exemplified by hematological malignancies, in which there is a growing list of entities that are defined by their genetic lesion(s); this is not (yet) the case in mature B-cell lymphomas. However, enhanced insights into the pathogenesis of this large and diverse group of lymphomas have emerged with the ongoing unraveling of a plethora of fascinating genetic abnormalities. The purpose of this review is to synthesize well-recognized data and nascent discoveries in our understanding of the genetic basis of a spectrum of mature B-cell lymphomas, and how this may be applied to contemporary clinical practice. Despite the explosion of new and exciting knowledge in this arena, with the potential for enhanced diagnostic and prognostic strategies, it is essential to remain cognizant of the limitations (and complexity) of genetic investigations, so that assays can be developed and used both judiciously and rationally.

Burkitt t(8;14)(q24;q32) and cryptic deletion in a CLL patient: report of a case and review of literature

A 53-year-old man diagnosed with chronic lymphocytic leukemia (CLL)-small lymphoma following splenectomy was found to have a t(8;14) with an apparent cryptic deletion of the MYC gene. This patient's spleen and bone marrow (BM) showed that 93% and approximately 70% of the viable cells, respectively, were lambda-monoclonal B-cells coexpressing CD5 with CD20, CD19, CD23, CD22, CD38, and low FMC-7. The smear showed a marked increase in small, mature lymphoid cells, with <2% prolymphocytes. The BM karyotype was 46,XY,t(8;14)(q24;q32),-18,+mar[3]/46,XY[27] and FISH analysis with an IGH/MYC green-red dual-fusion signal probe showed an atypical interphase result of one fusion, two green, and one red signal in 70% of the cells. The MYC dual red-green split-apart probe showed the expected t(8;14) pattern in 62% of the cells; however, sequential FISH on a t(8;14) GTG-metaphase showed the single fusion signal on derivative chromosome 8 and only a green signal on der(14) for the IGH/MYC dual-fusion probe and a green signal on der(14), red signal on der(8), and fusion signal on the normal chromosome 8 for the MYC split-apart probe. Thus, the apparently balanced t(8;14) had a cryptic deletion (approximately 1.6 Mb) between the red and the green regions flanking the MYC gene in the MYC split-apart probe, 128,585,631-130,226,339 bp from 8pter. The rarity of t(8;14) in CLL together with a cryptic deletion that probably includes the MYC gene in our CLL patient persuaded us to explore the clinicopathological role of MYC translocations by comparing disease progression in our patient and in other reported CLL cases.

Case of Chronic Lymphocytic Leukemia with Unusual Chromosome Aberrations

Chronic lymphocytic leukemia is one of the most common leukemias in the western world and consists of many chromosome aberrations. We report the case of a 74-year-old male patient with chronic lymphocytic leukemia with complex variant translocations t(8;22)(q24;q11) and der(8)t(6;8)(p21;p21) identified by chromosome banding analysis and confirmed by fluorescence in situ hybridization analysis of interphase cells. Because of the rarity of these changes, possible molecular mechanisms associated with this karyotype are discussed.