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The translocation t(14;18)(q32;q21) occurs in 70% of follicular lymphomas and places the BCL2 proto-oncogene, normally located at 18q21, under the control of the immunoglobulin heavy chain (IgH) gene at 14q32. Its detection by the polymerase chain reaction (PCR), made possible by the close clustering of most of the BCL2 breakpoints in the major breakpoint region (MBR) of the gene, has numerous clinical applications. Since the PCR covers shorter lengths of DNA than Southern blotting, PCR-based tests may be more susceptible to microheterogeneity in breakpoint location. There have been no published studies of the impact of breakpoint microheterogeneity on the detection rate of this translocation by PCR. We studied 30 follicular lymphomas with the t(14;18), in which a BCL2 MBR rearrangement had previously been demonstrated and mapped by conventional Southern blotting, by PCR with the commonly used IgH and BCL2 MBR primers. Twenty-five cases (83%) had a junction fragment demonstrable by PCR. All three cases in which the MBR rearrangement mapped outside of the 4.3-kb HindIII fragment containing the MBR, as determined by Southern blotting, were negative by PCR. In addition, two cases with rearrangements within the HindIII fragment were also negative. All negative results were repeated at least once and were confirmed to be true negatives by actin PCR. Our results suggest that negative PCR results in this setting are attributable to small variations in BCL2 MBR breakpoint location and cannot be interpreted without the corresponding conventional Southern blotting data. With this caveat in mind, PCR analysis for the t(14;18) remains an extremely useful technique, especially in the follow-up and monitoring for minimal residual disease in previously characterized cases of follicular lymphoma.
Diagn Mol Pathol 1992 Mar
PMID:Detection of rearrangements of the BCL2 major breakpoint region in follicular lymphomas. Correlation of polymerase chain reaction results with Southern blot analysis. 134 52

Some patients in apparent complete remission of hairy cell leukemia (HCL) after 2-chlorodeoxyadenosine (2-CdA) treatment may have minimal residual disease (MRD). This study examines detection of minimal residual disease by immunohistological staining using the monoclonal antibody (MoAb) B-ly 7 in 11 patients with complete remission of hairy cell leukemia (HCL) after 2-CdA therapy administered between 1990 and 1993. In all 11 cases, residual hairy cells could be detected by MoAb B-ly 7 (0.1 to 7.5%, median 0.65%). At a follow-up period of 7 - 29 months (median 19.3), 9 of these patients remained in complete remission, whereas 2 patients relapsed 22 and 27 months after 2-CdA therapy. To determine whether flow-cytometric analysis of hairy-cells in bone marrow aspirates and peripheral blood cells are comparable with results obtained by immunostaining with B-ly 7 in bone marrow biopsies, available data using CD-19/CD-11c double-staining were analyzed. In 5 of 10 cases no hairy-cells could be detected in bone marrow aspirates, and in 6 partly different cases no hairy-cells were detectable in peripheral blood using flow-cytometry, although immunostaining of bone marrow biopsies using B-ly 7 revealed hairy-cells (ranging form 0.1 to 7.5%) in these cases. These results indicate that therapy with 2-CdA does not eradicate hairy cell leukemia despite complete remission according to conventional criteria. Minimal residual disease might be responsible for subsequent relapse. We conclude that routine immunohistological examination of bone marrow biopsies with B-ly 7 should be performed for assessment of MRD. Flow cytometric investigations of mononuclear cells of bone marrow aspirate or peripheral blood seem valuable for regular long term monitoring of MRD, but does not substitute for immunostaining of bone marrow biopsies.
Blood Cells Mol Dis 1995
PMID:Minimal residual disease in hairy-cell leukemia after treatment with 2-chlorodeoxyadenosine. 884 43

The detection of clonality in B-cell lymphomas has been facilitated by polymerase chain reaction (PCR) analysis of the immunoglobulin heavy-chain gene (IgH) complementarity determining region 3 (CDR3) and size fractionation by polyacrylamide gel electrophoresis (PAGE). However, the detection of minor clonal populations and biallelic rearrangements and the isolation of monoclonal products from gels are sometimes problematic. This study evaluated whether denaturing gradient gel electrophoresis (DGGE), a technique that separates DNA based on nucleotide sequence rather than length, could alleviate these problems. A total of 32 selected cases was studied with a diagnosis of monoclonal (n = 10), polyclonal (n = 9), and indeterminate (n = 13) IgH gene rearrangements, which were determined by analysis of seminested IgH CDR3 PCR products in 8% PAGE. These cases were evaluated using DGGE of seminested IgH CDR3 PCR products that included a 40-bp GC clamp on the Jh primer. DGGE allowed the discrimination of monoclonal populations in 9 of 13 cases where 8% PAGE results were indeterminate. In addition, DGGE demonstrated biallelic IgH rearrangements in three cases where 8% PAGE revealed only one predominant product. DGGE facilitated the purification and isolation of clonal IgH CDR3 products for sequencing without prior cloning. As an adaptation of current IgH PCR protocols, DGGE can enhance the construction of tumor-specific CDR3 primers/probes for investigations of minimal residual disease.
Diagn Mol Pathol 1996 Sep
PMID:High-resolution analysis of immunoglobulin heavy-chain gene rearrangements using denaturing gradient gel electrophoresis. 886 28

This study evaluates the utility of fluorescence-based polymerase chain reaction (PCR) and PCR-SSCP methodologies to monitor the clonal relatedness of cells with bcl-2 major break point region (mbr)/JR fusion sequences in sequential samples from patients with follicular lymphoma (FL). Fluorescence-tagged PCR products from 2-4 sequential samples from seven FL patients were resolved in acrylamide gels and analyzed on an Applied Biosystems' automated DNA sequencer equipped with Genescan software. The amplicons were sequenced directly using automated DNA sequencing to obtain the precise amplicon size and base sequence. Fluorescence-based PCR-single-strand conformation polymorphism (SSCP) analysis performed to distinguish amplicons of similar size but of different base sequence. Amplification products differing by as few as 5 bp resolved clearly under fluorescent PCR assay conditions making possible by visual inspection alone the distinction of two products that otherwise appeared to be of similar size by conventional gel electrophoretic methods. The size of the amplicons as determined by Genescan software correlated exactly with the sizes generated by sequence analysis confirming the precision and accuracy of the fluorescent PCR assay. Under nondenaturing conditions, the mobility profiles of the amplicons from sequential samples with identical base sequence remained indistinguishable, whereas amplicons of similar size but of dissimilar base sequence from different patients exhibited distinct migration patterns. Thus, this study demonstrates that a combination of fluorescent PCR and PCR-SSCP assays for the detection of the t(14;18) provides an accurate measure of clonal relationship based on molecular size and sequence similarities without involving radiolabeling and sequencing strategies. Furthermore, the demonstrated preservation of junctional sequences across sequential biopsy specimens validates the use of PCR in the monitoring of minimal residual disease and eliminates concern about the detection of secondary, non-tumor-related translocations.
Diagn Mol Pathol 1997 Apr
PMID:The application of fluorescence-based PCR and PCR-SSCP to monitor the clonal relationship of cells bearing the t(14;18)(q32;q21) in sequential biopsy specimens from patients with follicle center cell lymphoma. 909 44

The complementarity determining region (CDR) III of the immunoglobulin heavy-chain (IgH) gene is a tumor-specific marker for B-cell malignancies that has been widely exploited for the monitoring of minimal residual disease in B-precursor acute lymphocytic leukemia. There are a number of technical problems in applying the same technology for B-cell non-Hodgkin's lymphoma (B-NHL). Several procedures have been useful in overcoming these unique problems encountered in obtaining the tumor-specific sequence of the IgH-CDRIII in B-NHL, including the use of denaturing gradient gel electrophoresis or micromanipulation of tissue sections in separating the tumor-specific CDRIII products from those of contaminating normal B-lymphocytes. Minor modifications of a commercial kit greatly improve the purity of the polymerase chain reaction (PCR) products for sequencing. Modifications of the 5'-ends of the VH and IH primers, coupled with the cycle sequencing technique, make it possible to obtain unambiguous sequences on direct sequencing of short PCR products. Computer informatics and programs that facilitate the design of tumor-specific primers and probes from CDRIII sequences are described.
Diagn Mol Pathol 1997 Jun
PMID:Obtaining clone-specific primer and probe for the immunoglobulin heavy-chain gene from paraffin-embedded tissue of B-cell lymphoma: technical considerations. 964 37

Detection of gene mutations by sensitive polymerase chain reaction (PCR)-based methods can allow to identify occult neoplastic cells in a great excess of nonmalignant cells. These molecular approaches have an enormous potential in terms of early diagnosis, detection of occult micrometastases of solid tumors, and minimal residual disease in patients with hematopoietic malignancies. Currently, the applications of such methods are limited, mainly because the high sensitivity required for the identification of rare mutated alleles can be achieved only in cases in which mutations occur in few specific codons of a gene or when the mutation is already known. No methods are available by which few alleles with unknown mutations in tumor genes can be recognized in a great excess of wild-type alleles. We have developed an extremely sensitive method, termed enriched single-strand conformational polymorphism (E-SSCP), which permits detection of a rare alleles with unknown mutations. The method is based on the observation that after a conventional SSCP analysis the vast majority of mutated bands migrate close to the wild-type bands. The area of the gel having the highest chance to hold mutated alleles is physically isolated and is used as substrate for a second round of SSCP. Serially diluted DNA samples containing gene mutations demonstrated detection of 1 mutant/10(6) normal alleles. The E-SSCP assay was first applied to six sputum samples of patients affected by lung cancers with known p53 mutations showing in sputa the same mutations observed in tumors. The technique was then applied to eight cytologically negative sputum samples obtained from patients who later developed a clinically manifested lung carcinoma. In three cases, harboring a p53 mutation in tumor tissue, the E-SSCP analysis allowed the detection of the mutations in sputa months before clinical diagnosis. In conclusion, we have presented a general, highly sensitive technique for the detection of unknown mutations that may have several potential applications and may hold considerable promise for the early detection and study of cancer.
Diagn Mol Pathol 1997 Aug
PMID:Enriched SSCP: a highly sensitive method for the detection of unknown mutations. Application to the molecular diagnosis of lung cancer in sputum samples. 936 Aug 39

Diagnostic techniques, routinely used in clinical practice for monitoring acute leukemia patients, are able to detect only 1-5% of malignant cells. At present, two main techniques are being introduced for detection of minimal residual disease (MRD) in leukemia, namely immunological marker analysis and the polymerase chain reaction (PCR) technique with general sensitivity of 10(-4)-10(-5). Immunological marker analysis allows detection of unusual and aberrant immunophenotypes, and is usually performed by flow cytometry. PCR analysis allows detection of leukemia-specific DNA sequences, such as fusion regions of chromosome aberrations and junctional regions of rearranged immunoglogulin (Ig) genes and T-cell receptor (TcR) genes. The applicability of the immunophenotyping and PCR-mediated MRD techniques is dependent on the type of leukemia. In virtually all acute lymphoblastic leukemias, PCR analysis of Ig and TcR genes can be used, and immunophenotypic MRD detection is also possible in 70-80% of cases. In AML, immunophenotypic MRD detection can be applied in approximately 80% of cases and PCR analysis of chromosome aberrations in 25-40%. Each MRD technique has its advantages and limitations, which have to be weighed carefully to make an appropriate choice. Furthermore, standardization of the MRD techniques is needed before they are used for stratification or adaptation of treatment protocols. Finally, the clinical impact of MRD detection for the various subtypes of acute leukemias has to be established.
Cytokines Mol Ther 1996 Jun
PMID:Detection of minimal residual disease in acute leukemia patients. 938 97

Spin-orbit MRD-CI calculations have been carried out for the potential energy surfaces of the seven lowest-lying electronic states of the BiOH molecule by employing relativistic effective core potentials. The HBiO isomer is found to be 4020 cm-1 less stable because of its inability to form multiple Bi-O bands. A bent 3A" BiOH ground state is predicted, which is split into all three of its components by spin-orbit coupling. The calculated X2A"-X1A' splitting is computed to be 5217 cm-1, but the corresponding X3-X2 value is only 29 cm-1. Fink et al. have observed spectral bands which appear with a Te value of 6200 cm-1 which are likely caused by BiOH. Since calculations at the same level for BiF underestimate the observed X2-X1 spin-orbit splitting by 650 cm-1, it appears that the present calculations are consistent with this experimental assignment. A vibrational progression with a 500 cm-1 frequency is also observed and this result fits in well with the computed Bi-O stretch omegae value of 527 cm-1. The calculations also find a relatively large 1Delta splitting (600 cm-1) because of the bent BiOH geometry, with comparatively strong transitions to the X1A' ground state, and it is suggested that the experimental BiOH assignment can be confirmed on this basis. Much stronger transitions to the 1Delta component should also be observed in emission in the 10 000 cm-1 range. Copyright 1997 Academic Press. Copyright 1997Academic Press
J Mol Spectrosc 1997 Nov
PMID:Ab initio Relativistic CI Calculations of the Spectroscopic Constants and Transition Probabilities for the Low-Lying States of the BiOH/HBiO Isomers 941 47

Fluorescence in situ hybridization (FISH) is a new technique that allows demonstrating of the bcr/abl gene fusion in bone marrow cells of patients with Philadelphia translocation (Ph)-positive chronic myeloid leukemia (CML). In this study, bone marrow samples of 150 patients were investigated routinely by interphase FISH, cytogenetics, and bone marrow histopathology. In 20 patients with reactive hyperplasia of the granulopoiesis and normal karyotypes, FISH revealed nonspecific bcr/abl fusion signals at a mean frequency of 2.7% of the cells examined. The cutoff level for specific fusion signals was set at three times the standard deviation (9.0%). None of the 29 cytogenetically Ph-negative patients with myeloproliferative disease other than CML had fusion signals exceeding 9%. The mean frequency of specific fusion signals in nontreated patients with CML (n = 59) was 92.7%, and 49.3% in patients with CML who received therapy (n = 42). For diagnosing Ph-positive CML, interphase FISH has been faster, more reliable, and more sensitive than cytogenetics, which was successful in 54 of 59 patients investigated at first diagnosis but only in 27 of 42 patients receiving therapy, and it failed to detect Ph-positive cells in three patients with CML. However, small percentages of less than 9.0% of cells with bcr/abl fusion signals were below the threshold of interphase FISH, thereby limiting its use for detecting minimal residual disease.
Diagn Mol Pathol 1997 Oct
PMID:Value of fluorescence in situ hybridization for detecting the bcr/abl gene fusion in interphase cells of routine bone marrow specimens. 945 87

Using genomic DNA from patients with follicular lymphoma, we performed polymerase chain reaction (PCR) amplifications to detect t(14;18) translocations. Unexpectedly large products of approximately 1 kilobase (kb) were detected by gel electrophoresis in 2 of 50 positive cases. In these 2 cases, sequence analyses showed novel breakpoints in the 3' untranslated region of bcl-2, approximately 800 bp downstream of the major breakpoint region (mbr). The breakpoints in IgH occurred in JH4 in one patient and JH5 in the other. Sequences just upstream of the new bcl-2 breakpoints suggest a mechanism of translocation that may include minisatellite core-mediated recombination. In one of our two patients with novel bcl-2 breakpoints, the approximately 1 kb product obtained using conventional mbr primers was detectable only when a nested PCR was performed. These findings have important implications for diagnosis and minimal residual disease detection in t(14;18)-positive lymphomas.
Diagn Mol Pathol 1998 Apr
PMID:Novel bcl-2 breakpoints in patients with follicular lymphoma. 978 6


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