Cyto-morphologic evaluation of bone marrow in infants with disseminated neuroblastoma.

We studied the prevalence and degree of tumor cell infiltration (TCI) in bone marrow (BM) aspirates of 89 infants with stage 4/4 S neuroblastoma and correlated them with MYCN gene status and patient outcome. TCI was scored 0, +, ++, and +++, the last corresponding to an infiltration greater than 10%. TCI 0 was more frequent in stage 4 than in stage 4 S. TCI + and ++ were equally represented. TCI +++ was found only in 9 patients, all with typical stage 4 features (bone or lung involvement). Overall survival was not significantly influenced by the presence and degree of TCI.

Differential diagnosis of lipoma-like lipoblastoma.

Lipoblastomas are rare benign tumors of white fatty tissue that occur primarily in young children. Occasionally, heterogeneity of morphological appearance and histological overlap with other lipogenic tumors are described. In such cases fluorescence in situ hybridization (FISH) analysis of PLAG1, a gene specifically rearranged in lipoblastoma, is necessary to prevent misdiagnosis. We present a case of lipoblastoma arising in an atypical site with histological features characteristic of lipoma. The correct diagnosis was made possible on cytogenetic grounds through the identification of the characteristic PLAG1-HAS2 fusion gene, thus allowing an appropriate clinical approach.

Inversion (11)(p15q22) with NUP98-DDX10 fusion gene in pediatric acute myeloid leukemia.

The inv(11)(p15q22), a rare but recurrent chromosome abnormality that creates a NUP98-DDX10 fusion gene, is associated with de novo or secondary myeloid malignancies. We report a case of acute monocytic leukemia presenting this rearrangement, studied using fluorescence in situ hybridization (FISH) and reverse transcriptase-PCR (RT-PCR). We also review the cases of inv(11) associated with NUP98-DDX10 reported in the literature.

Diagnostic identification of malignant cells in the cerebrospinal fluid by tumor-specific qRT-PCR.

Tumor specific quantitative RT-PCRs for two neuroblastoma specific molecular markers, tyrosine hydroxylase (TH) and GD2 synthase, were used to unequivocally demonstrate the neoplastic nature of the cells present in the cerebrospinal fluid of a neuroblastoma patient. After radical surgery of two separate tumoral lesions, localized in the extradural area, the patient presented with meningitis. Common sites of neuroblastoma metastatization, e.g. bone and bone marrow, were not infiltrated by tumor cells, as assessed by standard scintigraphy, morphological investigation and by sensitive and specific immunocytochemical and molecular assays. The results presented here demonstrate the successful use of tumor-specific qRT-PCRs in cerebrospinal fluid to investigate questionable clinical cases. The technique, which compared to other detection methods (e.g., immunocytochemistry) requires very few cells, yields unambiguous information once a suspected diagnosis has been formulated and a tumor-specific molecular marker is available.

Gain of 1q in pediatric myelodysplastic syndromes.

The presence of acquired clonal cytogenetic abnormalities in hematopoietic cells is one of the diagnostic hallmarks of myelodysplastic syndromes (MDS). Such anomalies may help in defining prognostic groups. We analyzed eight pediatric MDS, and herein describe three new cases, one de novo and two therapy-related, presenting an unbalanced rearrangement of 1q: one of them resulted in a derivative chromosome 6 apparently identical to a previously described one. We also review all the cases of gain of 1q reported in de novo and therapy-related childhood MDS.

MLL-MLLT10 fusion gene in pediatric acute megakaryoblastic leukemia.

The occurrence of MLL gene rearrangement in acute megakaryoblastic leukemia (AML-M7, acute myeloid leukemia, French-American-British type M7) is very rare and limited to pediatric age: in particular, MLL-MLLT10 fusion, previously reported as characteristic of monocytic leukemia, has been reported in only one case of pediatric megakaryoblastic leukemia. We describe the second case with this association in light of the few reported cases of AML-M7 with MLL and/or 11q23 involvement.

t(9;11)(p22;p15) with NUP98-LEDGF fusion gene in pediatric acute myeloid leukemia.

The rare t(9;11)(p22;p15) translocation is associated with adult acute myeloid leukemia (AML) with immature forms. We report a novel fusion of the NUP98 and LEDGF genes in a pediatric AML with intermediate characteristics between M2-M3 French-American-British (FAB) subtypes exhibiting the same chromosomal rearrangement. Fluorescence in situ hybridization (FISH) and reverse transcriptase-PCR (RT-PCR) studies identified the chimeric transcript product of in-frame fusion of NUP98 exon 8 to LEDGF exon 4.

Detection of neuroblastoma cells in bone marrow and peripheral blood by different techniques: accuracy and relationship with clinical features of patients.

PURPOSE: Detection of metastatic tumor cells in bone marrow (BM) and peripheral blood (PB) of children with neuroblastoma is crucial for prognosis and planning of therapy. Aims of this large descriptive repeated survey were to evaluate the diagnostic accuracy of different techniques in diagnostic samples obtained at several disease course time points and to correlate positive results with patient clinical features and outcome. EXPERIMENTAL DESIGN: BM aspirates, trephine biopsies, PB, and peripheral blood stem cell (PBSC) samples from Italian children with neuroblastoma were analyzed by morphological and histologic techniques, as well as by immunocytochemistry (IC) for disialoganglioside GD(2) and reverse transcription-PCRs (RT-PCRs) for tyrosine hydroxylase (TH) and pgp9.5 genes. The diagnostic odd ratio (DOR) was used to measure the accuracy of the different techniques. RESULTS: A total of 2,247 evaluations were done on 561 BM, 265 PB, and 69 PBSC samples from 247 patients. IC showed the best accuracy. Whereas TH RT-PCR accuracy was satisfactory, that of pgp9.5 was very low. Positive results obtained by IC in BM and PB samples at diagnosis from stage 1, 2, and 3 patients correlated with unfavourable outcome. No correlation was found between positive results obtained by IC or TH RT-PCR in BM, PB, and PBSC samples from stage 4 patients and their outcome. CONCLUSIONS: Because of its elevated diagnostic accuracy, IC may represent a useful adjunct to conventional morphological techniques, especially in view of its potential prognostic role in patients with localized disease. Longitudinal multicenter studies are warranted to definitely establish the clinical usefulness of TH RT-PCR.

MLL-MLLT10 fusion in acute monoblastic leukemia: variant complex rearrangements and 11q proximal breakpoint heterogeneity.

Cytogenetic studies of acute monoblastic leukemia cases presenting MLL-MLLT10 (alias MLL-AF10) fusion show a broad heterogeneity of chromosomal breakpoints. We present two new pediatric cases (French-American-British type M5) with MLL-MLLT10 fusion, which we studied with fluorescence in situ hybridization. In both we detected a paracentric inversion of the 11q region that translocated onto chromosome 10p12; one case displayed a variant complex pattern. We review the cytogenetic molecular data concerning the proximal inversion breakpoint of 11q and confirm its heterogeneity.

HCMOGT-1 is a novel fusion partner to PDGFRB in juvenile myelomonocytic leukemia with t(5;17)(q33;p11.2).

PDGFRB, a transmembrane tyrosine kinase receptor for platelet-derived growth factor, is constitutively activated by gene fusion with different partners in myeloproliferative/myelodysplastic disorders with peculiar clinical characteristics. Six alternative partner genes have been described thus far. In this study, we report the molecular cloning of a novel translocation t(5;17)(q33;p11.2) in a case of juvenile myelomonocytic leukemia. The novel partner gene was identified as HCMOGT-1 using 5'-rapid amplification of cDNA ends; fluorescence in situ hybridization and reverse transcriptase-PCR analyses confirmed that the translocation resulted in PDGFRB/HCMOGT-1 fusion. We show that the breakpoint of PDGFRB occurred at the same site of all previously reported PDGFRB translocations.

Uneventful outcome of unrelated hematopoietic stem cell transplantation in a patient with leukemic transformation of Kostmann syndrome and long-lasting invasive pulmonary mycosis.

Kostmann syndrome (KS) is an inherited hematological disorder characterized by an absolute neutrophil count (ANC) <0.2 x 109/L and life-threatening bacterial infections. Granulocyte-colony stimulating factor (G-CSF) makes it possible to reach an ANC of 1.0 x 109/L and consequently to reduce significantly the occurrence of severe infections. Absence of response to G-CSF, G-CSF receptor mutation, and leukemic transformation are absolute indications to perform hematopoietic stem cell transplantation (HSCT). Pulmonary mycosis does not represent an absolute contraindication to bone marrow transplantation (BMT), although a relapse rate of 30-50% has been reported, despite adequate medical and surgical treatment. Mycotic pneumonia recurrence shows a mortality rate above 80%, especially in the presence of persisting immunosuppression. We report on a KS patient with long-lasting fungal pneumonia who developed myelodysplasia and subsequent acute myeliod leukemia (AML) conversion resistant to antiblastic therapy. Despite surgical excision and secondary prophylaxis, recurrence of the pulmonary lesion occurred prior to the unrelated HSCT. In spite of these poor prognostic characteristics, outcome was uneventful and the patient is alive and well in continuous complete remission with no signs of fungal infection.

Cryptic translocation t(5;11)(q35;p15.5) with involvement of the NSD1 and NUP98 genes without 5q deletion in childhood acute myeloid leukemia.

The cryptic translocation t(5;11)(q35;p15.5), which creates a NSD1-NUP98 fusion gene, has been associated with a deletion of the long arm of chromosome 5, del(5q), in pediatric acute myeloid leukemia (AML) patients with differentiated phenotype. We screened five pediatric cases of AML with apparently normal karyotype by use of fluorescence in situ hybridization analysis and detected one case with early myeloid phenotype and poor clinical outcome, but with the same breakpoints and no del(5q). These findings point to the involvement of t(5;11) as an early event in leukemogenesis. Screening for this translocation in AML patients with apparently normal karyotype at onset is recommended.

XY female with a dysgerminoma and no mutation in the coding sequence of the SRY gene.

We report a 46,XY 11-year-old girl with pure gonadal dysgenesis who developed a dysgerminoma. The testis-determining gene SRY, a candidate for sex reversal, whose alterations seem to correlate with dysgerminoma, was analyzed and found to be normal; its coding sequence was negative for deletions and mutations. DMRT-1 gene mapping on 9p and DAX-1 on Xp21 were also normal. These results suggest the involvement of other genes in sex reversal and call into question the putative relationship between SRY alterations and dysgerminoma.

Is t(10;11)(p11.2;q23) involving MLL and ABI-1 genes associated with congenital acute monocytic leukemia?

Congenital, or perinatal, leukemias are rarely observed, but retrospective molecular studies seem to suggest a more frequent onset in prenatal life. Myelocytic types are common, and chromosome band 11q23 rearrangements at the MLL locus are characteristic genetic markers. The fusion of the MLL gene with one of its partners, ABI-1, has recently been described in two infant leukemia patients with monocytic involvement and good clinical outcome. We report a case of congenital monocytic leukemia with the same gene involvement and good response to chemotherapy. The blast metaphases were probed by fluorescence in situ hybridization, and t(10;11)(p11.2;q23) involving MLL and ABI-1 genes was demonstrated with the same breakpoint in ABI-1. The congenital presentation of this case suggests a possible relationship of this genetic event with in utero leukemogenesis.