Abnormalities on 1q and 7q are associated with poor outcome in sporadic Burkitt's lymphoma. A cytogenetic and comparative genomic hybridization study

Continuing challenges in childhood non-Hodgkin's lymphoma

Non-Hodgkin's lymphoma in children includes a number of different pathological subtypes and, with improved diagnostic techniques and better understanding of the natural history of each type, treatment strategies have become more tumour-specific. Original staging systems are now less useful in determining treatment stratification and there is a need for careful analysis of large cohorts of patients, treated in the same manner, to determine the clinical and biological features that, with current therapies, are of prognostic value. Novel imaging techniques, such as positron emission tomography, and molecular techniques to detect low-level marrow involvement are likely to be incorporated into new risk grouping. These will be used to determine the extent of initial disease and evaluate more accurately the speed and quality of response to chemotherapy. With high cure rates, it becomes particularly important to minimize late effects of therapy and the introduction of monoclonal antibodies in combination with chemotherapy may provide a method for improving outcome in poor risk groups and reducing sequelae by allowing reduction in chemotherapy in good risk patients.

Copy number gains on 22q13 in adenoid cystic carcinoma of the salivary gland revealed by comparative genomic hybridization and tissue microarray analysis

Adenoid cystic carcinoma (ACC) of the salivary gland is a neoplasm characterized by slow but inevitable local progression and terminal hematogenous metastasis. To detect novel imbalanced chromosomal regions associated with tumorigenesis, we used chromosomal comparative genomic hybridization to screen 27 ACC. The most common aberration was copy number gain of 22q13 (nine cases) followed by gains of 16p (seven cases) and 17q (four cases) and copy number losses on 6q (six cases). To further delineate the prevalence of 22q13 copy number gains in ACC, fluorescence in situ hybridization was performed for five bacterial/phage artificial chromosome (BAC/PAC) probes from the 22q13 consensus region with 57 ACC on a tissue microarray. The overall prevalence of copy number gains on 22q13 was 30% of the tumors in the fluorescence in situ hybridization analysis, irrespective of histologic differentiation (cribriform/tubular vs. solid) or tumor event (primary vs. recurrent). We therefore assume that copy number gain of 22q13 is a novel frequent finding in ACC that may be involved in the initial pathogenesis of this neoplasm by proto-oncogene activation.

Immunophenotypic and Cytogenetic Comparison of Waldenström's Macroglobulinemia with Splenic Marginal Zone Lymphoma

Some B-cell lymphoproliferative disorders displaying a serum monoclonal immunoglobulin (Ig) M protein could be difficult to differentiate from Waldenstrom's macroglobulinemia (WM). We report on the immunophenotypic and cytogenetic characteristics of 85 patients with WM and compare them with 29 patients with splenic marginal zone lymphoma (SMZL). For immunophenotyping, WM and SMZL constantly expressed panB-cell markers (CD19, CD20, CD22, and surface Ig). However, there were differences in the k/l ratio (1.2:1 for SMZL and 4.5:1 for WM) and in some markers such as CD22 and CD11c, which were overexpressed in patients with SMZL compared with patients with WM, whereas CD25 was more frequently positive in WM (88% vs. 44%). The CD103 antigen was always negative in WM, whereas it was positive in 40% of SMZL cases. The monoclonal antibody FMC7 was usually positive in both entities: heterogeneous in WM but homogeneous in SMZL. The combination of CD25 and CD22 could differentiate between WM and SMZL. The principal molecular abnormality in WM is 6q deletion (30% in our experience), whereas in SMZL the most common abnormalities are loss of 7q (19%) along with +3q (19%) and +5q (10%). Interestingly, the incidence of IgH rearrangement was low in WM (12%) and SMZL (10%). Immunophenotypic and molecular cytogenetic studies could help to distinguish WM from SMZL.

Molecular cytogenetic study of instability at 1q21∼q32 in adult acute lymphoblastic leukemia

In the present paper, we report a molecular cytogenetic study of 1q abnormalities associated with t(8;14)(q24;q32) in an adult common B acute lymphoblastic leukemia case with FAB-L2 morphology. The use of appropriate molecular cytogenetic probes allowed us to detect 13 different subclones showing heterogeneous chromosome 1 abnormalities. A complex pattern of rearrangements consisting of translocations, duplications, and inversions was observed. Breakage-fusion-bridge cycle and jumping translocation are hypothesized to have been involved in generating the large number of aberrations we detected.

Chromosomal abnormalities are related to location and grade of osteoarthritis

OBJECTIVE

To investigate the frequency of numerical aberrations of chromosomes 7, X and Y in patients with osteoarthritis (OA) by performing fluorescent in situ hybridization (FISH) studies on articular cartilage, and to correlate the chromosomal changes with the degree and location of articular involvement.

PATIENTS

Thirty-four women and 10 men with OA were included in the study. As a control group, 6 women and 5 men operated for orthopedic disorders other than OA were analyzed.

METHODS

FISH studies were performed on hip or knee cartilage, using two-color centromere-specific probes for chromosomes 7 & X for women and 7 & Y for men.

RESULTS

FISH analysis revealed that 46% of OA patients had numerical abnormalities of chromosomes 7, X or Y. An extra chromosome 7 (trisomy 7) was present in 35% of patients with chromosomal aberrations. All males with OA lost the Y chromosome while 15% of the women had loss of one chromosome X (monosomy X). Trisomy 7 was associated with hip OA (p=0.019) and advanced OA according to the Kellgren and Lawrence classification (p=0.05). None of the 11 controls showed abnormalities in the chromosomes analyzed.

CONCLUSIONS

FISH analysis showed the presence of numerical chromosomal abnormalities in the articular cartilage of patients with OA.

The role of molecular studies in lymphoma diagnosis: a review

Lymphoma classification is based on a multiparametric approach to diagnosis, in which clinical features, morphology, immunophenotype, karyotype and molecular characteristics are important to varying degrees. While in most cases, a diagnosis can be confidently established on the basis of morphology and immunophenotype alone, a small proportion of diagnostically difficult cases will rely on molecular studies to enable a definitive diagnosis. This review discusses the various molecular techniques available including Southern blotting (SB), polymerase chain reaction (PCR), fluorescence in situ hybridisation (FISH)--including multicolour-FISH/spectral karyotyping and comparative genomic hybridisation--and also gene expression profiling using cDNA microarray technology. Emphasis is given to the analysis of antigen receptor gene rearrangements and chromosomal translocations as they relate to lymphoma diagnosis and also in the setting of minimal residual disease (MRD) detection and monitoring. Laboratories performing these tests need to have expertise in these areas of testing, and there is a need for greater standardisation of molecular tests. It is important to know the sensitivity and specificity of each test as well as its limitations and the pitfalls in the interpretation of results. Above all, results of molecular testing should never be considered in isolation, and must always be interpreted in the context of clinical and other laboratory data.

Homogeneous immunophenotype and paucity of secondary genomic aberrations are distinctive features of endemic but not of sporadic Burkitt's lymphoma and diffuse large B-cell lymphoma withMYC rearrangement

The present study has compared immunohistological marker expression profiles and genomic imbalances in seven African endemic Burkitt's lymphomas (eBLs) with those in ten European B-cell lymphomas with MYC rearrangement as shown by fluorescence in situ hybridization (FISH) analysis. eBLs showed a typical histomorphology and a homogeneous immuno-profile: CD10+, CD38+, CD77+, bcl-2-, and IgM+. Epstein-Barr virus (EBV) DNA was present in all cases. On comparative genomic hybridization (CGH), only three out of six eBLs showed imbalances (median number of imbalances = 2), with gains on chromosome 17 in two eBLs. The European lymphomas were all highly proliferating, with a Ki-67 index of at least 90%, and included seven with morphology typical of sporadic Burkitt's lymphoma (sBL) and three immunoblastic diffuse large B-cell lymphomas with MYC rearrangement (MYCre+DLBCL). In contrast to eBL, the immuno-profiles of the European lymphomas were less homogeneous and inconsistent for CD10, CD38, CD77, IgM and bcl-2 expression. EBV DNA was not detected. In five of seven sBLs, CGH showed a higher number of imbalances (median = 6), with recurrent gains on chromosome 1q (3/7) and losses on 12q and 17p (2/7), whereas all three MYCre+DLBCLs had fewer imbalances (median = 4), with gains on 17q in two of three lymphomas. It is concluded that eBL has a homogeneous immunohistology and few secondary genomic aberrations, whereas MYC-rearranged and highly proliferating European B-cell lymphomas are a heterogeneous group that includes sBL and a subgroup of diffuse large B-cell lymphomas.