Isodicentric (X)(q13) in haematological malignancies: presentation of five new cases, application of fluorescence in situ hybridization (FISH) and review of the literature

Summary. Idic(X)(q13) represents a rare but recurrent chromosomal abnormality in haematological malignancies. We present five new cases characterized by this particular aberration and review the literature on this subject.
The patients were elderly females with a diagnosis of refractory anaemia (1/5), refractory anaemia with ringed sideroblasts (2/5), chronic myelomonocytic leukaemia (1/ 5), and Philadelphia chromosome-negative chronic myeloid leukaemia (1/5). Three out of the five patients demonstrated an increased proportion of bone marrow ringed sideroblasts. After a follow-up period of 30-57 months all patients but one are alive.
Idic(X)(q13) always occurred as the sole chromosomal abnormality, either in one or in two copies. We confirmed the dicentric nature of the aberration by fluorescence in situ hybridization (FISH) on metaphases as well as interphase nuclei using an X-chromosome-specific alpha-satellite probe, and performed chromosome painting to visualize possible additional chromosomal changes involving the X chromosomes.
Our findings and the data of 17 previously published cases indicate that idic(X)(q13): (1) may play a significant pathogenetic role in haematological malignancies affecting exclusively females and deriving predominantly from early progenitor cells; (2) is frequently associated with a pathological iron accumulation; (3) indicates a variable prognosis.     

Deletions of the long arm of chromosome 7 in myeloid disorders: loss of band 7q32 implies worst prognosis

Clinical and cytogenetic data were analysed in 54 patients with acute non-lymphocytic leukaemias (ANLL) or MDS (myelodysplastic syndromes) and deletion of the long arm of chromosome 7 (7q−), in order to determine if there is a commonly deleted region in 7q and to establish possible correlations between karyotypic features, such as karyotype pattern, karyotype complexity, associated anomalies, and/or the type of deleted segments, and outcome of patients with these disorders.
The median follow-up of our patients was 4 months (range 1–89), as was the median survival. In 30% of the cases there was a history of preceding MDS or previous chemotherapy. Clinical and cytogenetic remission was obtained in 7/36 patients treated with chemotherapy (CT). At the time of 7q− detection, three patients previously treated with CT for ANLL were in clinical remission. 5q− was the most recurrent associated abnormality. Complex karyotypes were observed in 68% of the cases. In univariate analysis, statistical differences in survival were observed according to diagnosis (therapy-related and secondary diseases had a worse prognosis than primary disorders), the chromosomal segments deleted (the loss of band 7q32 was of poor prognostic value), the karyotype complexity (patients with single anomalies did better than patients with complex anomalies) and the response to therapy (patients who achieved complete remission had a better survival probability). In multivariate analysis, the loss of band 7q32 was found to be significantly related to very poor prognosis. This finding suggests that band 7q32 may contain critical genes that should be explored at the molecular level.     

Phase I-II study of interferon-gamma and eflornithine (DFMO) in patients with advanced renal cell carcinoma, malignant melanoma and colorectal carcinoma

Eflornithine (DFMO) and interferon-gamma (IFN-gamma) are known to exert synergistic activity on inhibition of ornithinedecarboxylase (ODC) in vitro and in experimental animal tumors thereby inhibiting tumor proliferation. In this study, we prospectively investigated therapeutic effects and side effects of a combination of DFMO and IFN-gamma in 15 patients with renal cell carcinoma (RCC), 9 with malignant melanoma (MM), and 9 with colorectal carcinoma (CRC). DEMO was given orally at a dose of 3x4 g/day during the first 2 weeks of each month; IFN-gamma was administered daily subcutaneously during the DFMO administration periods and every other day during the following 2 weeks. The starting dose of IFN-gamma was 30 mu g/m(2) in the first 5 patients and 60 mu g/m(2) in the next 28. IFN-gamma dose was doubled every 4 weeks to a maximum dose of 120 mu g/m(2) and 240 mu g/m(2), respectively. Therapy was applied for three months in cases with stable disease or partial remission. In 15 patients treatment was stopped after 3 to 11 weeks after initiation of therapy because of tumor progression (14 cases) or severe side effects (1 case). In one out of 15 patients with renal cell carcinoma a partial response was observed lasting 7 months, 5 patients showed stable disease, and 9 progressed. In patients with malignant melanoma and colorectal carcinoma, stable disease was observed in one patient and progressive disease in 8 patients per group. The most frequent side effects were fever and gastrointestinal disturbances observed in 26 patients each. The results of this study indicate that DFMO combined with IFN-gamma has no significant therapeutic activity in patients with advanced renal cell carcinoma, malignant melanoma, and colorectal carcinoma.     

Non-Random Pattern of Integration for Epstein-Barr Virus with Preference for Gene-Poor Genomic Chromosomal Regions into the Genome of Burkitt Lymphoma Cell Lines

Background: Epstein-Barr virus (EBV) is an oncogenic virus found in about 95% of endemic Burkitt lymphoma (BL) cases. In latently infected cells, EBV DNA is mostly maintained in episomal form, but it can also be integrated into the host genome, or both forms can coexist in the infected cells. Methods: In this study, we mapped the chromosomal integration sites of EBV (EBV-IS) into the genome of 21 EBV+ BL cell lines (BL-CL) using metaphase fluorescence in situ hybridization (FISH). The data were used to investigate the EBV-IS distribution pattern in BL-CL, its relation to the genome instability, and to assess its association to common fragile sites and episomes. Results: We detected a total of 459 EBV-IS integrated into multiple genome localizations with a preference for gene-poor chromosomes. We did not observe any preferential affinity of EBV to integrate into common and rare fragile sites or enrichment of EBV-IS at the chromosomal breakpoints of the BL-CL analyzed here, as other DNA viruses do. Conclusions: We identified a non-random integration pattern into 13 cytobands, of which eight overlap with the EBV-IS in EBV-transformed lymphoblastoid cell lines and with a preference for gene- and CpGs-poor G-positive cytobands. Moreover, it has been demonstrated that the episomal form of EBV interacts in a non-random manner with gene-poor and AT-rich regions in EBV+ cell lines, which may explain the observed affinity for G-positive cytobands in the EBV integration process. Our results provide new insights into the patterns of EBV integration in BL-CL at the chromosomal level, revealing an unexpected connection between the episomal and integrated forms of EBV.     

Blood outgrowth endothelial cells from chronic myeloid leukaemia patients are BCR/ABL1 negative

The existence of adult haemangioblasts with dual haematopoietic and endothelial developmental potential was confirmed after detection of Ph⁺ vascular endothelial cells in chronic myeloid leukaemia (CML) patients. Blood outgrowth endothelial cells (OECs) from CML patients were found not to harbour the Philadelphia translocation and were thus not clonally related to BRC/ABL1 ⁺ hematopoietic progenitors, but comprised a distinct subfraction of endothelial cells. Remarkably, the frequency of CML-derived OECs was 9-fold higher as compared to healthy donors ( n  = 19 and n  = 300, respectively; P  <   0·0001) and these cells showed increased proliferative potential, possibly reflecting the mobilisation of OEC progenitors by pro-angiogenic cytokines.