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Biomedical subjects

J A Fletcher

Publications and source records attributed to J A Fletcher.

At least 55 records · Page 3Linked to original sources
PubMed1998

Chromosomal abnormalities in nodal and extranodal CD30+ anaplastic large cell lymphomas: infrequent detection of the t(2;5) in extranodal lymphomas.

To determine the significance of the t(2;5)(p23;q35) translocation in nodal and extranodal anaplastic large cell lymphoma (ALCL), we performed cytogenetic, molecular genetic, and immunohistochemical analyses of tumor tissues from 11 patients with CD30+ ALCL. Three of five patients with nodal ALCL had additional infiltration of the skin. Six patients had extranodal ALCL, two had primary intestinal ALCL, three had a primary cutaneous ALCL, and one had osseous ALCL. Cytogenetic investigation detected the t(2;5) in all patients with nodal ALCL but not extranodal ALCL. Tumor cells in t(2;5)+ lesions also stained immunohistochemically for p80NPM/ALK, whereas no staining for p80NPM/ALK was detected in extranodal ALCL. Two extranodal lesions had NPM/ALK fusion transcripts detected by nested reverse transcriptase-polymerase chain reaction. Fluorescence in situ hybridization analysis of these two lymphomas showed in one case a significant number (4%) of cells with a split hybridization signal, indicative of disruption of the NPM gene. Additional recurrent breakpoints observed in extranodal ALCL were 1p36, 6p25, and 8q24. Loss of genetic material occurred at 6q in one extranodal ALCL. Our results suggest that the t(2;5) more frequently plays a pathogenetic role in primary nodal than in extranodal ALCL and that this translocation may not be the primary event in some CD30+ ALCL.

Adult↗
PubMed1998

The HER-2/neu oncogene in breast cancer: prognostic factor, predictive factor, and target for therapy.

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. HER-2/neu has been widely studied in breast cancer. In this review, the association of HER-2/neu gene and protein abnormalities studied by Southern and slot blotting, immunohistochemistry, enzyme immunoassays, and fluorescence in situ hybridization with prognosis in breast cancer is studied in depth by review of a series of 47 published studies encompassing more than 15,000 patients. The relative advantages of gene amplification assays and frozen/fresh tissue immunohistochemistry over paraffin section immunohistochemistry are discussed. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The potential value of HER-2/neu status for the prediction of response to therapy in breast cancer is presented in the light of a series of recently published studies showing a range of impact on the outcome of patients treated with hormonal, cytotoxic, and radiation therapies. The evidence that HER-2/neu gene and protein abnormalities in breast cancer predict resistance to tamoxifen therapy and relative sensitivity to chemotherapy regimens including adriamycin is presented. The review will also evaluate the status of serum-based testing for circulating the HER-2/neu receptor protein and its ability to predict disease outcome and therapy response. In the final section, the review will briefly present preliminary data concerning the use of antibody-based therapies directed against the HER-2/neu protein and their potential to become a new modality for breast cancer treatment. The recently presented phase III clinical trial evidence that systemic administration of anti-HER2 antibodies (Herceptin), alone and in combination with cytotoxic chemotherapy in patients with HER-2/neu overexpressing primary tumors, can increase the time to recurrence and overall response rates in metastatic breast cancer is reviewed.

Animals↗
PubMed1998

Subtracted, unique-sequence, in situ hybridization: experimental and diagnostic applications.

Nonrandom chromosomal aberrations, particularly in cancer, identify pathogenic biological pathways and, in some cases, have clinical relevance as diagnostic or prognostic markers. Fluorescence and colorimetric in situ hybridization methods facilitate identification of numerical and structural chromosome abnormalities. We report the development of robust, unique-sequence in situ hybridization probes that have several novel features: 1) they are constructed from multimegabase contigs of yeast artificial chromosome (YAC) clones; 2) they are in the form of adapter-ligated, short-fragment, DNA libraries that may be amplified by polymerase chain reaction; and 3) they have had repetitive sequences (eg, Alu and LINE elements) quantitatively removed by subtractive hybridization. These subtracted probes are labeled conveniently, and the fluorescence or colorimetric detection signals are extremely bright. Moreover, they constitute a stable resource that may be amplified through at least four rounds of polymerase chain reaction without diminishing signal intensity. We demonstrate applications of subtracted probes for the MYC and EWS oncogene regions, including 1) characterization of a novel EWS-region translocation in Ewing's sarcoma, 2) identification of chromosomal translocations in paraffin sections, and 3) identification of chromosomal translocations by conventional bright-field microscopy.

Burkitt Lymphoma↗
PubMed1998

Congenital mesoblastic nephroma t(12;15) is associated with ETV6-NTRK3 gene fusion: cytogenetic and molecular relationship to congenital (infantile) fibrosarcoma.

Morphological, cytogenetic, and biological evidence supports a relationship between congenital (infantile) fibrosarcoma (CFS) and congenital mesoblastic nephroma (CMN). These tumors have a very similar histological appearance, and they are both associated with polysomies for chromosomes 8, 11, 17, and 20. Recently, CFS was shown to contain a novel t(12; 15)(p13;q25) translocation resulting in ETV6-NTRK3 gene fusion. The aims of this study were to determine whether congenital mesoblastic nephroma contains the t(12;15)(p13;q25) translocation and ETV6-NTRK3 gene fusion and whether ETV6-NTRK3 fusions, in CMN and CFS, antedate acquisition of nonrandom chromosome polysomies. To address these aims, we evaluated 1) ETV6-NTRK3 fusion transcripts by reverse transcriptase polymerase chain reaction and sequence analysis, 2) genomic ETV6-region chromosomal rearrangement by fluorescence in situ hybridization, and 3) chromosomal polysomies by karyotyping and fluorescence in situ hybridization. We report ETV6-NTRK3 fusion transcripts and/or ETV6-region rearrangement in five of six CMNs and in five of five CFSs. The ETV6-NTRK3 fusion transcripts and/or ETV-region chromosome rearrangements were demonstrated in two CMNs and one CFS that lacked chromosome polysomies. These findings demonstrate that t(12;15) translocation, and the associated ETV6-NTRK3 fusion, can antedate acquisition of chromosome polysomies in CMN and CFS. CMN and CFS are pathogenetically related, and it is likely that they represent a single neoplastic entity, arising in either renal or soft tissue locations.

Artificial Gene Fusion↗
PubMed1998

FGFR1 is fused with a novel zinc-finger gene, ZNF198, in the t(8;13) leukaemia/lymphoma syndrome.

Various histological subtypes of leukaemia and lymphoma are associated with diagnostic chromosome translocations, and substantial strides have been made in determining the specific oncogenes targetted by those translocations. We report the cloning of a novel fusion oncogene associated with a unique leukaemia/lymphoma syndrome. Patients afflicted with this syndrome present with lymphoblastic lymphoma and a myeloproliferative disorder, often accompanied by pronounced peripheral eosinophilia and/or prominent eosinophilic infiltrates in the affected bone marrow, which generally progress to full-blown acute myelogenous leukaemia within a year of diagnosis. A specific chromosome translocation, t(8;13)(p11;q11-12), is found in both lymphoma and myeloid leukaemia cells from these patients, supporting bi-lineage differentiation from a transformed stem cell. We find that the 8p11 translocation breakpoints, in each of four patients, interrupt intron 8 of the fibroblast growth factor receptor 1 gene (FGFR1). These translocations are associated with aberrant transcripts in which four predicted zinc-finger domains, contributed by a novel and widely expressed chromosome-13 gene (ZNF198), are fused to the FGFR1 tyrosine-kinase domain. Transient expression studies show that the ZNF198-FGFR1 fusion transcript directs the synthesis of an approximately 87-kD polypeptide, localizing predominantly to the cytoplasm. Our studies demonstrate an FGFR1 oncogenic role and suggest a tumorigenic mechanism in which ZNF198-FGFR1 activation results from ZNF198 zinc-finger-mediated homodimerization.

Amino Acid Sequence↗
PubMed1998

Primary cutaneous Ewing's sarcoma: immunophenotypic and molecular cytogenetic evaluation of five cases.

Cutaneous small blue cell tumors are relatively uncommon and include primary lesions of either adnexal or neuroendocrine differentiation, as well as metastatic disease. Extraosseous Ewing's sarcoma/malignant primitive neuroectodermal tumor (MPNET) rarely may occur as a primary, superficially based neoplasm in children and young adults. We describe a series of five cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor occurring as a primary cutaneous malignancy supported diagnostically both by immunohistochemical stains and fluorescence in situ hybridization (FISH). All five cases occurred as a solitary dermal nodule and were located in the lower extremities (3 cases), the axilla (1 case), and the flank (1 case). Three of the cases were clinically polypoid. Four of the five patients were female, and age at presentation ranged form 8 to 50 years of age (median, 18 years). All five tumors consisted of nodular proliferations of monomorphous, small blue cells with round, vesicular nuclei, and scant to moderate cytoplasm that were uniformly immunoreactive for the CD99 cell surface glycoprotein in a characteristic membranous pattern. Fluorescence in situ hybridization analysis of paraffin-embedded tissue revealed that three of four tumors were positive for a chromosomal translocation involving the EWS locus at 22q12, seen in more than 90% of cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor. One case was not analyzable. All five patients were treated using local excision, and two patients additionally received postoperative chemotherapy and radiotherapy. Clinical follow-up is available in three cases (median duration, 33 months) and to date none has shown evidence of either local recurrence or metastasis. Because similar cases reported in the literature have likewise had favorable clinical courses after excision, primary cutaneous Ewing's sarcoma/malignant primitive neuroectodermal tumor may represent a clinically favorable subset of this otherwise highly aggressive neoplasm.

Adolescent↗
PubMed1998

Spindle cell rhabdomyosarcoma (so-called) in adults: report of two cases with emphasis on differential diagnosis.

Spindle cell rhabdomyosarcoma (RMS) is a recently described variant of embryonal RMS that carries a relatively favorable prognosis when compared with other forms of RMS. To date, spindle cell RMS has been described only in children. The authors have identified two unusual cases occurring in adults using the following criteria: tumors composed mainly of fascicular, relatively monomorphic spindle-shaped cells that show unequivocal immunohistochemical and ultrastructural evidence of myogenic differentiation. The tumors were identified in a 38-year-old woman and a 56-year-old man, arising in the cheek and left hemidiaphragm, respectively. Both were treated with surgical resection and chemotherapy. The first patient died of uncontrolled local recurrence of her tumor at 27 months after diagnosis, and the second died of metastatic disease at 13 months follow-up. The tumors were composed mainly of fascicles of spindle cells with palely eosinophilic cytoplasm admixed diffusely with sparse polygonal, rounded, or strap-shaped rhabdomyoblasts with brightly eosinophilic cytoplasm and with cross-striations in the first case only. Immunostaining for muscle-related antigens showed staining for smooth-muscle actin (focal), pan-actin HHF-35, desmin, fast myosin, myoglobin, and MyoD1. Both cases were negative for S-100 protein. On electron microscopy, both cases showed neoplastic rhabdomyoblasts with clear-cut sarcomeric differentiation in many of the tumor cells. Spindle cell RMS poses special problems in differential diagnosis when arising in adults and should be distinguished from leiomyosarcoma, malignant peripheral nerve sheath tumor with heterologous rhabdomyoblastic differentiation (malignant Triton tumor), and fibrosarcoma. In view of the good prognosis afforded children with spindle cell RMS and in light of the chemoresponsive behavior of RMS in general, we feel that it is important to identify tumors that meet the criteria for spindle cell RMS occurring in the adult population. However, based on these two cases, it is possible that spindle cell RMS occurring in adults may not be associated with such a favorable outcome.

Actins↗
PubMed1998

Inflammatory myofibroblastic tumor: cytogenetic evidence supporting clonal origin.

The inflammatory myofibroblastic tumor (IMT) is a distinctive but controversial lesion, usually occurring during childhood, composed of fascicles of bland myofibroblastic cells admixed with a prominent inflammatory infiltrate consisting of lymphocytes, plasma cells, and eosinophils. Often affecting the lung and associated with constitutional symptoms, this lesion has been variously termed plasma cell granuloma, inflammatory pseudotumor, inflammatory myofibrohistiocytic proliferation, and inflammatory fibrosarcoma to reflect divergent views concerning its pathogenesis and level of malignancy. Cytogenetic analysis of an intra-abdominal myxoid hamartoma, a probable variant of this lesion, and a pulmonary IMT demonstrated clonal chromosomal abnormalities, lending support to the view that the IMT might be a neoplasm. There have been few cases studied to date, however, and the extent of cytogenetic anomalies in IMTs is not known. Karyotype analyses were performed on IMTs showing typical histologic features from three children. In addition, one case was studied by fluorescence in situ hybridization. Seventeen of 20 metaphase cells examined from a pulmonary IMT in a 5.5-year-old girl had an abnormal 47,XX+r(ring) karyotype. Fluorescence in situ hybridization studies demonstrated that the ring chromosome contained sequences of chromosome 8. Of 40 metaphase cells studied from a mesenteric IMT in an 8-month-old boy, 12 showed clonal aberrations, characterized as 43,XY,add(1)(p36),add(2)(p24),-6,der(14,22)(q10;q10),-19. Each of 20 metaphase cells examined from a retroperitoneal IMT in a 14-year-old girl contained complex clonal and nonclonal aberrations, characterized as 46-47,X,-X,add(2)(p22),add(2)(q13),+add(2)(q13),+5,-6,+i(7)(p10),add(8)( p11.2),+del(9)(p13),add(11)(p11.2)add(11)(q25),-13,-16,-18,add(19)(q13.1 ),add(19)(q13.1),+20,-21,-22,+mar1,+1-2mars. The presence of clonal chromosomal aberrations in all of the three tumors indicates that the IMT is a neoplastic proliferation.

Adolescent↗
PubMed1998

Various regions within the alpha-helical domain of the COL1A1 gene are fused to the second exon of the PDGFB gene in dermatofibrosarcomas and giant-cell fibroblastomas.

Dermatofibrosarcoma protuberans (DFSP) and its juvenile form, giant-cell fibroblastoma (GCF), are uncommon infiltrative tumors of the dermis, which present unique cytogenetic features, such as the reciprocal translocation t(17;22) or, more commonly, supernumerary ring chromosomes containing sequences from chromosomes 17 and 22. We have recently shown that these aberrations are cytogenetic manifestations of gene fusions between the platelet-derived growth factor B-chain gene (PDGFB), the cellular equivalent of the v-sis oncogene, and the collagen type 1 alpha 1 gene (COL1A1), the major protein constituent of the extracellular matrix in connective tissue of skin. We now report characterization of COL1A1/PDGFB chimeric genes at the RNA and DNA sequence levels in a series of DFSPs and GCFs. All 16 tumors studied contained the COL1A1/PDGFB gene. The location of breakpoints within COL1A1 varied greatly, but was always limited to the region encoding the alpha-helical domain. The PDGFB segment of the chimeric transcript always starts with exon 2, placing PDGFB under the control of the COL1A1 promoter and removing all known elements negatively controlling PDGFB transcription and translation. Production of these aberrant transcripts in fibroblasts, the suspected cell of origin of DFSP/GCF, likely causes autocrine stimulation and cell proliferation. No specific function has yet been assigned to exon 2 of PDGFB, and this exon does not encode for the mature growth factor. Its retention in all chimeric COL1A1/PDGFB genes suggests that it is important for the normal processing of the PDGFB polypeptide.

Adult↗
PubMed1998

The pericentromeric inversion, inv (6)(p25q13), is a novel diagnostic marker in chondromyxoid fibroma.

Chondromyxoid fibroma is a benign bone tumor that arises most commonly in the metaphysis of long bones in young adults. The cytogenetic features of this tumor are not well known. In this study, four chondromyxoid fibromas were karyotyped after short-term cell culture. All of the tumors contained clonal rearrangements of chromosome 6, and each of these rearrangements involved band 6q13. Two tumors contained a pericentromeric inversion, inv (6)(p25q13), which was described recently in chondromyxoid fibroma. 6q13 rearrangements are not associated with other types of bone and soft tissue tumors, and the inv (6)(p25q13) is reported only in chondromyxoid fibroma. Hence, this cytogenetic marker might be helpful in distinguishing chondromyxoid fibroma from chondrosarcoma and other histologic mimics. The consistent occurrence of 6q13 rearrangements suggests a specific oncogenic mechanism in chondromyxoid fibroma, most likely involving oncogene activation.

Adolescent↗
PubMed1997

Human pancreatic cancer cells (MPanc-96) recognized by autologous tumor-infiltrating lymphocytes after in vitro as well as in vivo tumor expansion.

A human tumor line designated MPanc-96 has been established from a poorly differentiated primary pancreatic adenocarcinoma. MPanc-96 has a doubling time of 27 hr and grows as a confluent monolayer in various culture media. Cytogenetic analysis of in vitro-cultured tumor cells revealed a large number of clonal chromosomal aberrations, confirming their neoplastic origin. MPanc-96 grows in SCID mice when injected s.c. Xenografts established from the tumor line had a similar histology as the primary tumor. Tumor-infiltrating lymphocytes (TILs) were isolated from the primary tumor, and cytotoxic T lymphocytes (CTLs) were generated after activation on immobilized anti-CD3 monoclonal antibody (MAb) for 48 hr, expansion in low-dose IL-2 and repeated stimulation with irradiated MPanc-96 tumor cells. The generated CTLs lysed fresh autologous tumor cells as well as in vitro and in vivo expanded tumor cells from passages 9-53, suggesting that one or more tumor-associated antigens (TAAs) are stably expressed. CTLs lysed tumor cells in an HLA-class I-restricted fashion but showed no significant cytotoxicity against autologous fibroblasts, several allogeneic pancreatic cancer cell lines or K562. Our findings may be significant for the design of an animal model for studying the mechanisms of immunotherapy in human pancreatic cancer or for the identification of TAAs in pancreatic cancer.

Adenocarcinoma↗
PubMed1997

Methods for automatic multiparameter analysis of fluorescence in situ hybridized specimens with a laser scanning cytometer.

Multiparameter laser scanning cytometry has been applied to the automatic counting of probe spots and the simultaneous measurement of cellular DNA for fluorescence in situ hybridization (FISH) prepared specimens counterstained with propidium iodide. Relatively low resolution imaging, highly variable probe fluorescence, spectral overlap of probe with counterstain fluorescence, and autofluorescence required the development of an image processing method to detect and isolate FISH probe spots. Inability to properly apportion detected probe spots because of overlapping probe spot images in the same cell required development of a method to eliminate cell data whenever spots in that cell could not be reliably isolated. Laser scanning cytometry incorporating these methods to determine per cell probe spot count and DNA is demonstrated on tissue cultures and peripheral blood cells using different centromeric FISH probes with either FITC or Spectrum Green labeling.

Cells, Cultured↗
PubMed1997

Isolation and characterization of a mammalian homolog of the Drosophila white gene.

The Drosophila melanogaster white gene is a member of the ABC transporter superfamily of ATPase transmembrane proteins and is involved in the cellular uptake of guanine and tryptophan. We have cloned and sequenced human and mouse homologs of white which share 55-58% amino acid similarity with the Drosophila protein. Northern analysis reveals that the mammalian homolog is highly expressed in several tissues, including brain, spleen, lung and placenta. We have localized the gene to human chromosome 21q22.3 by means of fluorescence in situ hybridization and linkage analysis using a (CA)n polymorphism. The human homolog maps to the interval between D21S212 and D21S171, a region which includes loci for bipolar affective disorder and a recessive form of deafness. Since tryptophan is a precursor for the neurotransmitter serotonin and neurotoxic metabolites of the kynurenine pathway, we propose that the human homolog of white is a suitable candidate gene for these neurological disorders in humans.

ATP-Binding Cassette Transporters↗
PubMed1997

Terminal differentiation of human liposarcoma cells induced by ligands for peroxisome proliferator-activated receptor gamma and the retinoid X receptor.

Induction of terminal differentiation represents a promising therapeutic approach to certain human malignancies. The peroxisome proliferator-activated receptor gamma (PPAR gamma) and the retinoid X receptor alpha (RXR alpha) form a heterodimeric complex that functions as a central regulator of adipocyte differentiation. Natural and synthetic ligands for both receptors have been identified. We demonstrate here that PPAR gamma is expressed at high levels in each of the major histologic types of human liposarcoma. Moreover, primary human liposarcoma cells can be induced to undergo terminal differentiation by treatment with the PPAR gamma ligand pioglitazone, suggesting that the differentiation block in these cells can be overcome by maximal activation of the PPAR pathway. We further demonstrate that RXR-specific ligands are also potent adipogenic agents in cells expressing the PPAR gamma/RXR alpha heterodimer, and that simultaneous treatment of liposarcoma cells with both PPAR gamma- and RXR-specific ligands results in an additive stimulation of differentiation. Liposarcoma cell differentiation is characterized by accumulation of intracellular lipid, induction of adipocyte-specific genes, and withdrawal from the cell cycle. These results suggest that PPAR gamma ligands such as thiazolidinediones and RXR-specific retinoids may be useful therapeutic agents for the treatment of liposarcoma.

Adipocytes↗
PubMed1997

Cytologic and fluorescence in situ hybridization (FISH) examination of metanephric adenoma.

Metanephric adenoma is a recently described benign renal neoplasm with distinctive histologic features. The cytologic appearance and fluorescence in situ hybridization (FISH) studies of this tumor have not been described. We present a case from a 48-yr-old woman. Cytologically, the cells were arranged in tight, short papillae and loose sheets. The cells had scant cytoplasma, round monotonous nuclei with fine even chromatin and rare small nucleoli. Immunohistochemistry revealed no reactivity for epithelial membrane antigen (EMA), keratins (AE1/AE3, callus, 34BE12), or carcinoembryonic antigen (CEA). FISH showed a disomic pattern for chromosomes 7, 17, and for the chromosome 3 short arm. The differential diagnosis includes Wilms' tumor, renal adenoma, papillary renal cell carcinoma, and metastatic tumors. Both immunohistochemistry and FISH may be of help in distinguishing some of these lesions.

Adenoma↗
PubMed1997

Cytologic and cytogenetic analysis of metanephric adenoma of the kidney: a report of two cases.

Metanephric adenoma is a recently described renal neoplasm. Because follow-up to date has been benign, accurate diagnosis on fine-needle aspiration material may be important for appropriate clinical management. A retrospective analysis of fine-needle aspiration material from two metanephric adenomas was performed. The aspirates were cellular and composed of many small to large tightly packed clusters of cells and short papillae. Occasional tubules, rosettes, and glomeruloid-like structures were seen. The tumor cells had very scant cytoplasm; small, oval to round, uniform, overlapping nuclei with fine delicate chromatin; and minute or absent nucleoli. Rare psammoma bodies were noted. Atypia, pleomorphism, necrosis, and mitoses were absent. Cytogenetic analysis showed normal karyotypes in both cases. The cytologic differential diagnosis included Wilms' tumor, renal-cortical adenoma, papillary renal cell carcinoma, and neuroendocrin, and metastatic tumors. We conclude that metanephric adenoma has unique cytologic features that may allow distinction from other renal neoplasms on fine-needle aspiration material. In difficult cases, ancillary studies may be helpful.

Adenoma↗