Analysis of microsatellite instability in chronic lymphoproliferative disorders.
ABSTRACT Microsatellite instability (MSI) represents one specific pattern of genomic instability and is one of the genetic lesions most frequently detected in human neoplasia. Although MSI has been found to be associated with a wide variety of solid cancers, its involvement in lymphoid malignancies is virtually unexplored. In this study, we have investigated the presence of MSI in chronic lymphoproliferative disorders by comparing the pattern of nine microsatellite repeats (two tetranucleotides, two trinucleotides, and five dinucleotides) on autologous germline and tumor DNA of 23 patients, including 17 with B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL), four with hairy cell leukemia, one with lymphoplasmacytoid lymphoma, and one with T-cell chronic lymphocytic leukemia. All samples at diagnosis displayed a germline pattern of the microsatellites examined, thus suggesting that MSI is not involved in the pathogenesis of these lymphoproliferations. Also, no microsatellite alterations were observed in consecutive samples of B-CLL/SLL obtained from the same patient at various stages of the disease both before and after chemotherapy. Conversely, alterations in 3/9 microsatellite repeats were detected in one case of Richter's syndrome which had evolved from a pre-existent B-CLL/SLL phase. Overall, the low frequency of MSI among chronic lymphoproliferative disorders adds further weight to the common view that the mechanisms and patterns of genomic instability in lymphoid neoplasia differ markedly from those commonly observed in solid cancers.
Article: Microsatellite instability analysis in typical and progressed mantle cell lymphoma and B-cell chronic lymphocytic leukemia.[show abstract] [hide abstract]
ABSTRACT: Microsatellite instability (MSI) is characterized by tumor-associated alterations in the germline size of microsatellite repeats caused by a reduced efficacy of the DNA mismatch repair machinery. The aim of this study was to investigate the presence of MSI in a number of cases of indolent and aggressive mantle cell lymphoma (MCL) and B-cell chronic lymphocytic leukemia (B-CLL) to determine its possible role in the initial development and progression of these disorders. We examined the presence of MSI in 28 B-CLL, 24 typical and 4 transformed B-CLL (Richter's syndrome) and 29 MCL, 19 typical and 10 blastoid variants by using a panel of 10 microsatellite markers and analyzed them using an AbiPrism 310 DNA sequencer. Fisher's exact test was used to compare categorical variables and Mann-Whitney's U-test for continuous variables. MSI alterations were not observed in any case of MCL or Richter's syndrome and in only three (13%) patients with typical B-CLL. Two of these patients also had loss of heterozygosity in one of the 10 sites examined. These patients presented with a more advanced stage, diffuse bone marrow involvement, and poorer performance status than patients without these alterations. These findings indicate that MSI is not involved in the pathogenesis or progression of B-CLL and MCL but may appear in a small subset of patients with advanced B-CLL.Haematologica 03/2001; 86(2):181-6. · 6.42 Impact Factor
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ABSTRACT: Development of multiple tumors of different histopathologic types may suggest a profound generalized genetic defect, such as malfunction of DNA mismatch repair (MMR) mechanism. Defects in this mechanism are best reflected in microsatellite instability (MSI). We aimed to determine the role of MSI in a group of patients with dual malignancies and compared the data with that of patients with a single malignancy. Fifty patients were enrolled in the study, of whom 16 patients developed both solid and hematologic nonfamilial malignancies, 18 patients developed a single matched hematologic malignancy, and 16 a single matched solid malignancy. Five microsatellite markers were replicated by polymerase chain reaction (PCR) after DNA extraction from paraffin-embedded tissue blocks and analyzed by the GeneScan Analysis Software. The MSI-high phenotype was defined as instability in at least 40% of the examined loci. A higher prevalence of MSI-high phenotype was found in patients with dual malignancies (31.3%) compared with patients with single hematologic (5.6%) or solid malignancy (6.3%) (P = 0.0498 and 0.07, respectively). In conclusion, defects in DNA MMR mechanism may have an important role in the development of multiple sporadic nonfamilial malignancies.Molecular Carcinogenesis 04/2006; 45(3):175-82. · 3.16 Impact Factor
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ABSTRACT: The gene coding for the human CD5 lymphocyte surface receptor maps to the 11q12.2 region, which is in the vicinity of a region commonly affected by multiple somatic mutations in human cancers. The 5'-flanking region of the human CD5 gene includes an evolutionarily conserved (TC)n(CA)n microsatellite (MS) of potential utility as a marker for genome instability. The aim of the present study was to investigate the value of the CD5 MS as a marker for instability in different tumor types, particularly in B-cell leukemia and lymphoma. The CD5 MS and a panel of 10 MS markers were analyzed by using a polymerase chain reaction (PCR)-based method and polyacrylamide sequencing gels. This was done in several hematopoietic and non-hematopoietic cell lines, as well as in 28 cases of B-cell chronic lymphocytic leukemia (B-CLL), 19 mantle cell lymphomas (MCL) and 45 head and neck carcinomas (HNC). The frequency of CD5 MS abnormalities found among HNC was similar to that reported for other well known MS markers at loci near known and suspected cancer genes. However, instability at the CD5 MS was the most frequent MS abnormality among B-CLL and MCL. The inclusion of MS markers at chromosome 11q may be especially informative for genome instability analyses of certain B-cell leukemias and lymphomas.Haematologica 04/2002; 87(3):235-41. · 6.42 Impact Factor