1 Divisione di Ematologia I, A.O. V. Cervello, Palermo, Italy
2 Onco Ematologia Pediatrica, Ospedale dei Bambini "G. Di Cristina", Palermo, Italy
3 Onco Ematologia Pediatrica, Ospedale Pausilipon, ...Napoli, Italy
4 Division of Immunology, Childrens Hospital, Harvard Medical School, Boston, USA
5 Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
6 Cambridge Institute for Medical Research, Addenbrookes Hospital, Cambridge, UK
7 Oncoematologia Pediatrica, A.O.U. Meyer, Firenze, Italy
Correspondence: Maurizio Aricò, U.O. Oncoematologia Pediatrica, Azienda Ospedaliero-Universitaria Meyer, viale Pieraccini, 24, 50139 Firenze, Italy. E-mail: m.arico{at}meyer.it
Mutations of UNC13D have been described in patients affected by familial hemophagocytic lymphohistiocytosis (FHL3). The Munc13-4 protein contributes to the priming of the secretory granules. Mutation in this gene results in defective cellular cytotoxicity and the familial hemophagocytic lymphohistiocytosis clinical picture. Among reported mutations, few are predicted to impair splicing. Yet, functional impact of these mutations has not been addressed. We identified 18 out of 31 familial hemophagocytic lymphohistiocytosis families showing at least one mutation responsible for splicing error. We identified some known and three novel splicing mutations: one falls at the acceptor site of exon 11 and 2 are deep intronic mutations in IVS1 and in IVS30. We demonstrated that these deep intronic mutations affect regulatory sequences causing aberrant splicing. We report that UNC13D mutations leading to splicing errors represent the majority of mutations observed in familial hemophagocytic lymphohistiocytosis. This finding has implications for designing strategies for analysis of the families with suspected familial hemophagocytic lymphohistiocytosis.
Key words: lymphohistiocytosis, splicing.
Vincristine is an antineoplastic drug with a well known efficacy for the treatment of acute lymphoblastic leukemia and many solid tumors. No more than 20 pediatric patients with vincristine-induced ...vocal cord palsy have been reported, and to the best of our knowledge this is the first case where glutamic acid was administered with the aim of preventing a relapse of laryngeal dysfunction.
The larynx paralysis presented with hoarseness and stridor in a Caucasian 18-month-old girl and spontaneously resolved in about a month. In order to administer a subsequent full dose of vincristine, our patient received oral glutamic acid whose efficacy against vincristine neurological side effects has been previously reported.
Since in our patient the amino acid proved to be ineffective in the prevention of laryngeal paralysis relapse, we suggest that a dose reduction of vincristine should be preferred by oncologists as an initial approach after a case of drug-induced vocal cord palsy.
Diamond Blackfan anemia typically presents in infants and is often associated with many kinds of malformations. Severity of anemia often needs transfusional support in the first months of life. We ...describe here a patient with Diamond Blackfan anemia related to a RPL5 mutation. The patient had no physical abnormalities and experienced a very late onset of transfusion dependency.
The American Society for Clinical Pathology (ASCP), College of American Pathologists (CAP), Association for Molecular Pathology (AMP), and the American Society of Clinical Oncology (ASCO) have been ...recently strongly recommended the evaluation of mismatch repair status (MMS) as molecular biomarkers in colorectal cancer for a better prognostic stratification of patients. This recommendation is emphasized by the recent evidence of Microsatellite Instability (MSI) as a predictive marker for chemotherapy and immunotherapy.
In this scenario, the validation of molecular biomarker testing methods seems to be essential to design the most appropriate tailored therapy and the most suitable care strategy, respectively.
In this study, we validated an alternative method based on capillary electrophoresis system label-free PCR (Qiaxcel system) to evaluate the MSI Bethesda Panel. We also parallel the results with a standard approach.
Our data showed total concordance with the standard approach, with a highly time-efficient and easy procedure combined with high sensitivity for MSI detection.
Alternative capillary electrophoresis based on label-free PCR such as the Qiaxel system is a very sensitive and specific method to detect MSI for the management of patients with colorectal cancer. This procedure is adequate and suitable in diagnostic routine for the evaluation of microsatellite repeats compared to standard procedures.
We screened 100 children with acute lymphoblastic leukemia (ALL) to assess the incidence of single amino acid change A91V in perforin. Heterozygous A91V was found in 12/100 patients and 5/127 ...controls (OR, 3.4; 95%CI: 1.15-9.95; p=0.014). A91V is a novel and frequent predisposing factor for childhood ALL.
BACKGROUND. Monoallelic and biallelic mutations of the PRF1 gene have been reported in some cases of childhood lymphoma. Anaplastic large cell lymphoma (ALCL) accounts for 10% to 15% of all childhood ...lymphomas. To assess the possible role of PRF1 mutations in ALCL, the authors screened a series of patients collected by the Associazione Italiana di Ematologia Oncologia Pediatrica (AIEOP). METHODS. The authors investigated 44 patients with ALCL by direct sequence of the PRF1 gene. To address the issue of the prevalence of the most frequently observed PRF1 mutations in the control population, the authors examined a series of 400 healthy white control subjects for the 272C>T mutation (A91V). RESULTS. A total of 6 different mutations were identified in 12 patients (27.3%). Eleven patients had 1 mutation whereas 1 patient was found to have 2 mutations. Of the 6 PRF1 mutations identified, 2 were novel mutations: 529C>T (resulting in R177C) and 1471G>A (resulting in D491N). The remaining 4 mutations were previously described; in particular, the 272C>T mutation (resulting in the A91V amino acid change) was found in 8 patients, whereas the 368G>A (R123H), 695G>A (R232H), and 1262T>G (F421C) mutations were all found in 1 case each. Overall, the incidence of PRF1 mutations was found to be significantly higher in patients with ALCL compared with 400 control subjects, among whom only heterozygous A91V was observed in 41 subjects (10.2%) (chi-square test, 10.9; P <.01). CONCLUSIONS. Patients with childhood ALCL have a higher probability of being a carrier of a PRF1 mutation compared with healthy controls, suggesting a possible predisposing role. Cancer 2007.
Introduction.Pax-5 gene codifies for a transcription factor central to B-cell differentiation and function, expressed during the early stage of differentiation and alternatively spliced during B-cell ...development. In addition to the full-length isoform (Pax-5a), isoforms arising from the inclusion or exclusion of exons 2, 7, 8, and/or 9, and lacking the DNA-binding and the transactivating domains, have been described. These isoforms and their levels of expression increase during B-cell maturation. In particular, Pax-5b isoform (deleted of exon 2), resulting in protein with partial DNA-binding domain, is related with the differentiation stage. Recently, mutations of Pax-5 gene were reported in 31.7% of 242 children (Mullighan, Nature 2007) and 30% of 119 adults (Familiades, ASH 2007 abs. 2806) with B-cell precursor acute lymphoblastic leukemia (ALL). We investigated Pax-5 gene mutations and isoforms expression in patients with ALL at the diagnosis and in selected cell populations from control subjects.
Methods.Pax-5 mutations and mRNA isoforms were investigated by sequence analysis. Pax-5a and Pax-5b expression levels were evaluated by quantitative PCR in leukemic cells. Total RNA was obtained from leukemic blasts of 95 patients with B-cell precursor ALL at diagnosis, 45 adults and 50 children. These last had been selected according to the presence of adverse translocations: BCR/ABL p190 (n=10), E2A-PBX1 (n=10), TEL/AML (n=10), MLL/AF4 (n=10), or none (n=10). mRNA was obtained from purified peripheral blood CD19+ lymphocytes (6 samples), from bone marrow CD34+ hematopoietic progenitor cells (6 samples), and pro-B CD34+CD19+ cells (3 samples) from a total of 8 healthy bone marrow donors.
Results. Pax-5 gene point mutations were found in 8/45 adults (18%) and 14/50 children (28%) (p=n.s.), resulting in a total of 20 different mutations. Mutations were located as follows: exon 2 (53G>C, 76delG, 101C>G, 113G>A, 197G>A), exon 3 (223A>G, 247delA, 296T>C), exon 4 (446A>T, 526G>A), exon 5 (580A>C, 601G>A), exon 6 (625C>T, 716G>A), exon 7 (836C>A), exon 8 (955G>A, 964insC, 971A>G), exon 9 (1058C>T), exon 10 (1133G>A). There was no correlation between the presence of mutations and the listed genetic subtypes. Pax-5 alternative splicing was observed in 47/95 cases (49%): 29/45 adults (64%) and 18/50 children (36%) (p=n.s.). Alternative splicing resulted in increased frequencies of the Pax-5b isoform and the deletion of exons 8 and/or 9; furthermore, a novel isoform resulting from the skipping of exon 5 was documented. On the contrary, only the fulllenght isoform was present in CD34+ progenitors and CD34+CD19+ cells from healthy donors, in which deleted isoforms were detected only at the stage of mature B-lymphocytes.
Conclusion: Pax-5 mutations are frequent in childhood and adult ALL and are scattered all over the gene. We extend the current knowledge on their pathogenic role by demonstrating that alternative splicing is a common event in these patients. Imbalance between the fulllength and the Pax-5b isoforms is expected to affect the maturation of the B-cell and its propensity to apoptosis (Robichaud Nucleic Acids Res 2008), thus contributing to the process of leukemogenesis. Based on our findings, this mechanism acts broadly and is independent of the most common ALL genetic translocations.
Mutations of PRF1 and MUNC13–4 genes, involved with cellular cytotoxicity, are associated with the familial form of Hemophagocytic Lymphohistiocytosis (HLH) type 2 (FHL2) and 3 (FHL3). In all ...patients with HLH, in which PRF1 mutations had been excluded, we screened MUNC13–4 mutations.
The 32 exons and their proximal flanking regions of MUNC13–4 gene were sequenced by “cycle sequencing” approach (BigDye Terminator, Applied Biosystems).
Of 60 patients, 21 had MUNC13–4 mutations. 5 were reported mutations: 753+1G>T, 817C>T (R273X); 1389+1G>A; 1822del 12 bp (del V608-A611); 2346–9delGGAG (R782FsX12). Of 16 novel mutations 2 (2212C>T and 2650C>T) introduce a stop codon (at Q738 and Q884); 4 cause frameshift: 441delA (P147fsX14), 532delC (Q178fsX70), 3082delC (L1028fsX), and 3226insG (H1076fsX51). Of 8 missense mutations 175G>A (A59T), 419T>C (I140T), 610A>G (M204B), 1241G>T (R414L), 1847A>G (E616G), 2039G>C (R680P), 2570T>G (F857C), 2782C>T (R928C), 6 fall within the protein functional domains; each of the 2 falling outside was associated with 2 additional pathogenic mutations.
The remaining novel 1992+5 G>A and 2448insC −12 fall outside the coding region but are close enough to induce alternative splicing. We identified polymorphisms 279C>T and 3198A>G. The 2599A>G (K867E) transition was found in several unrelated families, including one homozygous parent. To assess its frequency we studied 50 consecutive newborns, of which 64% were heterozygous.
To understand the effects of the mutations we analysed Munc13–4 protein expression from CTL and/or NK cells by western blot using an antibody raised against amino acids 1–262. Trace amounts of protein could be detected only in 5 patients. Analysis of granule polarisation in 2 patients with trace amounts of Munc13–4 protein showed many more docked granules visible than in controls, consistent with a block in granule secretion in these patients.
Median age at diagnosis of FHL3 was 6.5 months, but 8/21 (38%) patients were diagnosed when older than 5 years, with one young adult of 18 years. CNS disease was present in 10 patients; NK was markedly reduced or absent in all patients tested. MUNC13–4 mutations were found in 35% of our HLH patients non type-2. Mutations were almost entirely different from those reported so far and scattered over different exons, but in far most cases they fall within the protein functional domain. Since these patients may develop the disease during adolescence or even later on, not only pediatric but also as adults hematologists should include FHL-2 and 3 in the differential diagnosis of children and young adults with fever, cytopenia, splenomegaly and hypercytokinemia.
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