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Biomedical subjects

Massimo Fabrizio Martelli

Publications and source records attributed to Massimo Fabrizio Martelli.

8 recordsLinked to original sources
PubMed2006

Mutated nucleophosmin detects clonal multilineage involvement in acute myeloid leukemia: Impact on WHO classification.

Because of a lack of specific clonality markers, information on lineage involvement and cell of origin of acute myeloid leukemia with normal karyotype (AML-NK), is missing. Because Nucleophosmin (NPM) gene is frequently mutated in AML-NK and causes aberrant NPM cytoplasmic localization (NPMc+), it was used as an AML lineage clonality marker. Clonal NPM exon 12 mutations were detected in myeloid, monocytic, erythroid, and megakaryocytic cells but not in fibroblasts or endothelia that were laser-microdissected from 3 patients with NPMc+ AML. Aberrant cytoplasmic expression of mutated NPM proteins was identified with anti-NPM antibodies in 2 or more myeloid hemopoietic cell lineages in 99 (61.5%) of 161 of NPMc+ AML paraffin-embedded bone marrow biopsies; lymphoid involvement was excluded in 3 investigated cases. These findings suggest that NPMc+ AML derives from either a common myeloid or earlier progenitor. Immunohistochemical studies show that varying combinations and ratios of NPMc+ leukemic cells from distinct lineages are responsible for heterogeneity within each French-American-British (FAB) classification type and for NPMc+ AML falling into different FAB categories. These findings question the value of FAB criteria in subdividing the WHO category of "AML not otherwise characterized" and suggest that, for clinical use, NPMc+ AML be provisionally regarded as a separate AML with prognostic significance.

Biomarkers, Tumor↗
PubMed2006

Denaturing high-performance liquid chromatography: a valid approach for identifying NPM1 mutations in acute myeloid leukemia.

NPM1 gene mutations are the most frequent genetic lesion in the 60% of adult acute myeloid leukemias (AMLs) with normal karyotype and no evidence of typical fusion genes (BCR/ABL1, PML/RARA, AML1/ETO, CBFB/MYH11, DEK/CAN). Using direct sequencing we previously identified six different heterozygous mutants within exon 12 encoding the nucleophosmin C-terminus. Because of these mutations the shuttling protein nucleophosmin is aberrantly delocalized in the cytoplasm of leukemic cells (NPMc+). Here, we designed and tested a denaturing high-performance liquid chromatography (DHPLC) assay to detect NPM1 mutated variants. To assess specificity, sensitivity, reliability, and reproducibility, we analyzed DNA from 120 primary adult AMLs and compared DHPLC results with immunohistochemistry and sequencing. All electropherogram profiles in the 26 NPMc+ leukemias were different from the wild type, indicating 100% sensitivity. Sequencing categorized mutations A, B, and D, and all mutation A cases gave identical elution profiles. The other mutations showed typical chromatograms, with mutations B and D differing for one nucleotide. Elution profiles and sequencing also identified four new variants. Our results suggest that DHPLC detects NPM1mutations as well as direct sequencing and immunohistochemistry, providing a helpful approach in the diagnosis of NPMc+ AML.

Amino Acid Sequence↗
PubMed2006

Prevalence, incidence and clinical outcome of hepatitis B virus and hepatitis C virus hepatitis in patients undergoing allogeneic hematopoietic stem cell transplantation between 2001 and 2004.

The prevalence, incidence and clinical course of viral hepatitis were prospectively determined in consecutive recipients of T-cell depleted hematopoieic stem cell transplants (49 mismatched, 60 matched, mean age 38 years; range 11-65). The prevalence of hepatitis B virus (HBV) was 15.6% and that of hepatitis C virus was 3.7% (HCV). HBV reactivated in one patient. Another developed ex novo acute hepatitis B which progressed to chronic hepatitis. There were no new cases of hepatitis C or worsening of pre-transplant HCV infections. HBV and HBC did not affect the outcome of T-cell depleted hematopoieic stem cell transplantation. Surveillance is important given the risk of HCV and HBV infection and/or reactivation and the efficacy of the new anti-hepatitis drugs.

Adolescent↗
PubMed2004

Submicroscopic deletions in 5q- associated malignancies.

BACKGROUND AND OBJECTIVES: The deletion of the long arm of chromosome 5 is common in myelodysplastic syndromes (MDS) but is not limited to the 5q- syndrome as it is also seen in acute myeloid leukemia (AML), where it is often associated with other karyotypic aberrations. The aim of this study was to investigate whether deletions of known suppressor sequences occur in myeloid malignancies associated with 5q-. DESIGN AND METHODS: Thirty patients with MDS or AML were selected for the presence of a 5q karyotypic deletion, either isolated (19 cases) or associated with other chromosome changes (11 cases). Multiple fluorescent in situ hybridization (FISH) in interphase nuclei was applied in all cases using a panel of eleven probes for known suppressor genes or loci deleted in MDS/AML. Metaphase FISH was also performed to clarify discrepancies between conventional and molecular cytogenetics. RESULTS: No additional deletions were found in nineteen cases with an isolated 5q-. Mono-allelic deletions where found in 9/11 cases, 3 of which were related to monosomies by conventional cytogenetics. Interphase-FISH showed p53, AML1, D13S25, NF1, or Ikaros in six out of nine (66%) patients with 5q- and additional karyotypic changes. Metaphase FISH was helpful in assigning some of these cryptic events to non-proliferating cells. INTERPRETATION AND CONCLUSIONS: Our study emphasizes that isolated 5q- is the marker of a highly stable clone in both MDS and AML. AML with isolated 5q- are molecularly closer to 5q- syndrome than to AML with complex changes. Interphase-FISH data strongly support a mutator phenotype underlying complex karyotypes with a 5q deletion.

Aged↗
PubMed2004

Partial duplication of the MLL oncogene in patients with aggressive acute myeloid leukemia.

BACKGROUND AND OBJECTIVES: MLL translocations generate a fusion gene between the 5' end of MLL and the 3' end of different partner genes. Several chromosomal mechanisms including complex and cryptic changes lead to these recombinations. Our objective was to analyze the molecular composition of chromosomes in complex karyotypes with specific MLL translocations. DESIGN AND METHODS: Fluorescence in situ hybridization (FISH) was performed in two acute leukemias (AL), one acute myeloid leukemia (AML) M5a, and one treatment-related-AL (t-AL), to investigate the nature of complex changes accompanying the respective t(9;11)(p22;q23)-MLL/AF9 and t(11;16)(q23;p13.3)-MLL/CBP. RESULTS: In the case with the MLL/AF9 chimeric transcript, duplication of a der(1) originated from an additional unbalanced translocation between the der(9)t(9;11) and a chromosome 1. The 5'AF9/3'MLL chimeric gene was present on both der(1). In the second case, there was a t(11;16)(q23;p13.3) producing one der(11) and two der(16) which derived from both homologs. One der(16) was present in multiple copies all containing the 5'CBP/3'MLL fusion gene. INTERPRETATION AND CONCLUSIONS: In both cases the 3' end of MLL was present in multiple copies. Mitotic recombination and non-disjunction may underlie the extra derivatives in both cases. In this genomic imbalance not only the 5'MLL but also the 3'end of MLL could play a critical role in the leukemic process.

Acute Disease↗
PubMed2002

Complex variant Philadelphia translocations involving the short arm of chromosome 6 in chronic myeloid leukemia.

BACKGROUND AND OBJECTIVES: Around 5% of chronic myeloid leukemias (CML) are characterized by complex variant Philadelphia (Ph) translocations involving one or more chromosomal regions in addition to 9 and 22. The BCR/ABL1 fusion gene is usually found on der(22). The additional gene(s) involved in complex variant Ph rearrangements have not been characterized. DESIGN AND METHODS: We performed fluorescent in situ hybridization (FISH) in three complex variant Ph translocations involving the short arm of chromosome 6 in addition to 9 and 22. The BCR/ABL1 D-FISH probe was applied to localize the BCR/ABL1 fusion gene as well as the 5'ABL1 and the 3'BCR. Locus-specific probes were used to narrow the 6p breakpoint. RESULTS: In all cases the BCR/ABL1 fusion gene was located on the Ph chromosome whereas the reciprocal ABL1/BCR gene was detected only in patient #2. On 6p, breakpoints were narrowed to three different regions: centromeric to the human major histocompatibility complex (MHC), between PAC 524E15 and PAC162J16, in the first patient, and telomeric to the MHC, between PAC 329A5 and PAC 145H9, and between PAC 136B1 and PAC 206F19, in the second and third patients, respectively. In patients #2 and 3 a chromosomal rearrangement different from a true complex variant was discovered. In both cases, a classical t(9;22) was associated with an additional translocation involving the der(9)t(9;22). INTERPRETATION AND CONCLUSIONS: Rearrangements at 6p in complex Ph aberrations involve more than one gene/locus. Classical t(9;22), masked by additional chromosomal rearrangements, can resemble complex variant Ph translocations, and can be detected only using appropriate FISH probes.

Aged↗