Showing papers by "Jonathan A. Fletcher published in 2004"

Biology of gastrointestinal stromal tumors.

Abstract: Once a poorly defined pathologic oddity, in recent years, gastrointestinal stromal tumor (GIST) has emerged as a distinct oncogenetic entity that is now center stage in clinical trials of kinase-targeted therapies. This review charts the rapid progress that has established GIST as a model for understanding the role of oncogenic kinase mutations in human tumorigenesis. Approximately 80% to 85% of GISTs harbor activating mutations of the KIT tyrosine kinase. In a series of 322 GISTs (including 140 previously published cases) studied by the authors in detail, mutations in the KIT gene occurred with decreasing frequency in exons 11 (66.1%), 9 (13%), 13 (1.2%), and 17 (0.6%). In the same series, a subset of tumors had mutations in the KIT-related kinase gene PDGF receptor alpha (PDGFRA), which occurred in either exon 18 (5.6%) or 12 (1.5%). The remainder of GISTs (12%) were wild type for both KIT and PDGFRA. Comparative studies of KIT-mutant, PDGFRA-mutant, and wild-type GISTs indicate that there are many similarities between these groups of tumors but also important differences. In particular, the responsiveness of GISTs to treatment with the kinase inhibitor imatinib varies substantially depending on the exonic location of the KIT or PDGFRA mutation. Given these differences, which have implications both for the diagnosis and treatment of GISTs, we propose a molecular-based classification of GIST. Recent studies of familial GIST, pediatric GIST, and variant forms of GIST related to Carney's triad and neurofibromatosis type 1 are discussed in relationship to this molecular classification. In addition, the role of mutation screening in KIT and PDGFRA as a diagnostic and prognostic aid is emphasized in this review.

KIT-negative gastrointestinal stromal tumors: proof of concept and therapeutic implications.

Abstract: The diagnosis of gastrointestinal stromal tumor (GIST) is currently based on morphologic features and immunohistochemical demonstration of KIT (CD117). However, some tumors (in our estimation approximately 4%) have clinicopathologic features of GIST but do not express KIT. To determine if these lesions are truly GISTs, we evaluated 25 tumors with clinical and histologic features typical of GIST, but with negative KIT immunohistochemistry, for KIT and PDGFRA mutations using DNA extracted from paraffin-embedded tissue. Most tumors originated in the stomach (N = 14) or omentum/mesentery (N = 5). The neoplasms were composed of epithelioid cells (13 cases), admixed epithelioid and spindle cells (8 cases), or spindle cells (4 cases). Absence of KIT expression was confirmed by immunoblotting in 5 cases. Tumor karyotypes performed in 4 cases were noncomplex with monosomy 14 or 14q deletion, typical of GIST. Mutational analysis revealed PDGFRA and KIT mutations in 18 and 4 tumors, respectively, whereas 3 tumors did not have apparent KIT or PDGFRA mutations. The PDGFRA mutations primarily involved exon 18 (N = 15) and included 11 tumors with missense mutation in codon 842 (PDGFRA D842V or D842Y). In conclusion, a small subset of GISTs with otherwise typical clinicopathologic and cytogenetic features do not express detectable KIT protein. When compared with KIT-positive GISTs, these KIT-negative GISTs are more likely to have epithelioid cell morphology, contain PDGFRA oncogenic mutations, and arise in the omentum/peritoneal surface. Notably, some KIT-negative GISTs contain imatinib-sensitive KIT or PDGFRA mutations; therefore, patients with KIT-negative GISTs should not, a priori, be denied imatinib therapy.

USP6 and CDH11 oncogenes identify the neoplastic cell in primary aneurysmal bone cysts and are absent in so-called secondary aneurysmal bone cysts.

Abstract: Aneurysmal bone cyst (ABC) is a locally recurrent bone lesion that has been regarded as a reactive process. Recently, a neoplastic basis in primary ABC was evidenced by demonstration of clonal chromosome band 17p13 translocations that place the USP6 (TRE2 or TRE17) oncogene under the regulatory influence of the highly active CDH11 promoter. Herein, we report CDH11 and/or USP6 rearrangements in 36 of 52 primary ABCs (69%), of which 10 had CDH11-USP6 fusion, 23 had variant USP6 rearrangements without CDH11 rearrangement, and three had variant CDH11 rearrangements without USP6 rearrangement. USP6 and CDH11 rearrangements were restricted to spindle cells in the ABC and were not found in multinucleated giant cells, inflammatory cells, endothelial cells, or osteoblasts. CDH11 and USP6 rearrangements did not correlate with recurrence-free survival, or with other clinicopathological features. CDH11 and USP6 rearrangements were not found in any of 17 secondary ABC associated with giant cell tumor, chondroblastoma, osteoblastoma, and fibrous dysplasia. These findings demonstrate that primary ABC are mesenchymal neoplasms exhibiting USP6 and/or CDH11 oncogenic rearrangements. By contrast, secondary ABC lack CDH11 and USP6 rearrangements, and although morphological mimics of primary ABC, appear to represent a non-specific morphological pattern of a diverse group of non-ABC neoplasms.

Midline Carcinoma of Children and Young Adults With NUT Rearrangement

Abstract: Purpose A balanced chromosomal translocation, t(15;19), resulting in the BRD4-NUT oncogene, has been identified in a lethal carcinoma of young people, a disease described primarily in case reports. We sought to amass a more definitive series of tumors with NUT and/or BRD4 gene rearrangements and to determine distinct clinicopathologic features. Patients and Methods Carcinomas (N = 98) in young individuals (median age, 32.5 years) were screened for NUT and BRD4 rearrangements using dual-color fluorescence in situ hybridization. Four published carcinomas with BRD4 and NUT rearrangements were also evaluated. Immunophenotypic analyses were performed. Results Eleven tumors had NUT gene rearrangements, including eight with BRD4-NUT fusions and three with novel rearrangements, which were designated as NUT variant. All NUT-rearranged carcinomas (NRCs) arose from midline epithelial structures, including the first example arising below the diaphragm. Patients were young (median age, 17.6 years). Squamous differenti...

KIT mutations are common in testicular seminomas.

Abstract: Expression of KIT tyrosine kinase is critical for normal germ cell development and is observed in the majority of seminomas Activating mutations in KIT are common in gastrointestinal stromal tumors and mastocytosis In this study we examined the frequency and spectrum of KIT mutations in 54 testicular seminomas, 1 ovarian dysgerminoma and 37 non-seminomatous germ cell tumors (NSGCT) Fourteen seminomas (259%) contained exon 17 point mutations including D816V (6 cases), D816H (3 cases), Y823D (2 cases), and single examples of Y823C, N822K, and T801I No KIT mutations were found in the ovarian dysgerminoma or the NSGCTs In transient transfection assays, mutant isoforms D816V, D816H, Y823D, and N822K were constitutively phosphorylated in the absence of the natural ligand for KIT, stem cell factor (SCF) In contrast, activation of T801I and wild-type KIT required SCF Mutants N822K and Y823D were inhibited by imatinib mesylate (Gleevec, previously STI571) whereas D816V and D816H were both resistant to imatinib mesylate Biochemical evidence of KIT activation, as assessed by KIT phosphorylation and KIT association with phosphatidylinositol (PI) 3-kinase in tumor cell lysates, was largely confined to seminomas with a genomic KIT mutation These findings suggest that activating KIT mutations may contribute to tumorigenesis in a subset of seminomas, but are not involved in NSGCT

Mechanisms of oncogenic KIT signal transduction in primary gastrointestinal stromal tumors (GISTs)

Abstract: Most gastrointestinal stromal tumors (GISTs) express constitutively activated forms of the KIT receptor tyrosine kinase protein, resulting from oncogenic mutations in the extracellular, juxtamembrane, or kinase domains. KIT oncoproteins are detected early in GIST tumorigenesis, and most GIST patients respond well to treatment with the KIT kinase inhibitor imatinib mesylate (STI571, Gleevec®). However, GISTs can develop resistance to imatinib, and additional therapeutic strategies are needed. Little is known about oncogenic KIT signal transduction in GISTs, and whether the type of KIT mutation accounts for selective activation of downstream signaling intermediates. We therefore evaluated KIT downstream signaling profiles in 15 primary GISTs with mutations in KIT exons 9, 11, 13, and 17, and in two human GIST cell lines. All GISTs showed constitutive phosphorylation at KIT tyrosine residues Y703 and Y721. Additionally, most GISTs showed activation of MAPK p42/44, AKT, S6K, STAT1, and STAT3. STAT5 and JNK were not demonstrably activated in any GIST. Using GIST in vitro models, we showed that activation of MAPK p42/44, AKT, and S6K was KIT dependent, whereas STAT1 and STAT3 phosphorylation was only partially dependent on KIT activation. Correlation of activated signaling pathways with the type of KIT mutation revealed low levels of AKT phosphorylation in exon 9 mutant GISTs in contrast to a subset of GISTs with exon 11 mutations. However, additional factors are likely to modify the engagement of signaling pathways in GISTs as suggested by the fact that four GISTs with identical KIT exon 9 mutations had differential activation of MAPK p42/44 and STAT proteins. In summary, in this first report on KIT signal transduction in primary GISTs and GIST cell lines, we identified pathways that are constitutively activated in a KIT-dependent manner and therefore warrant further study as molecular targets in GISTs.

USP6 (Tre2) Fusion Oncogenes in Aneurysmal Bone Cyst

Abstract: Aneurysmal bone cyst (ABC) is a locally aggressive osseous lesion that typically occurs during the first two decades of life. ABC was regarded historically as a nonneoplastic process, but recent cytogenetic data have shown clonal rearrangements of chromosomal bands 16q22 and 17p13, indicating a neoplastic basis in at least some ABCs. Herein we show that a recurring ABC chromosomal translocation t(16;17)(q22;p13) creates a fusion gene in which the osteoblast cadherin 11 gene (CDH11) promoter region on 16q22 is juxtaposed to the entire ubiquitin-specific protease USP6 (Tre2) coding sequence on 17p13. CDH11-USP6 fusion transcripts were demonstrated only in ABC with t(16;17) but other ABCs had CDH11 or USP6 rearrangements resulting from alternate cytogenetic mechanisms. CDH11 is expressed strongly in bone, and our findings implicate a novel oncogenic mechanism in which deregulated USP6 transcription results from juxtaposition to the highly active CDH11 promoter.

The chimeric FUS/CREB3l2 gene is specific for low‐grade fibromyxoid sarcoma

Abstract: Low-grade fibromyxoid sarcoma (LGFMS) is a variant of fibrosarcoma that was recognized as a distinct tumor entity only quite recently. We previously described a translocation, t(7;16)(q33;p11), that resulted in a fusion of the FUS and CREB3L2 (also known as BBF2H7) genes in two soft tissue tumors that fulfilled morphologic criteria for LGFMS. To delineate the spectrum of tumors that may harbor the FUS/CREB3L2 gene, we selected 45 low-grade spindle cell sarcomas for reverse transcriptase polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH) analyses; none of these tumors had originally been diagnosed as LGFMS. Furthermore, also included were two benign soft tissue tumors and nine high-grade sarcomas with supernumerary ring chromosomes or 7q3 rearrangement and three tumors diagnosed as LGFMS prior to the genetic analysis. Of the 59 tumors analyzed, 12 were FUS/CREB3L2-positive, all of which were diagnosed at histopathologic re-examination as being LGFMS, of both the classical subtype and the subtype with giant collagen rosettes. The breakpoints in the fusion transcripts were always in exons 6 or 7 of FUS and exon 5 of CREB3L2. The results indicated that FUS/CREB3L2 is specifically associated with LGFMS and that RT-PCR or FISH analysis may be useful for the differential diagnosis.

Overexpression, Amplification, and Androgen Regulation of TPD52 in Prostate Cancer

Abstract: Gains in the long arm of chromosome 8 (8q) are believed to be associated with poor outcome and the development of hormone-refractory prostate cancer Based on a meta-analysis of gene expression microarray data from multiple prostate cancer studies (D R Rhodes et al, Cancer Res 2002;62:4427-33), a candidate oncogene, Tumor Protein D52 (TPD52), was identified in the 8q21 amplicon TPD52 is a coiled-coil motif-bearing protein, potentially involved in vesicle trafficking Both mRNA and protein levels of TPD52 were highly elevated in prostate cancer tissues Array comparative genomic hybridization and amplification analysis using single nucleotide polymorphism arrays demonstrated increased DNA copy number in the region encompassing TPD52 Fluorescence in situ hybridization on tissue microarrays confirmed TPD52 amplification in prostate cancer epithelia Furthermore, our studies suggest that TPD52 protein levels may be regulated by androgens, consistent with the presence of androgen response elements in the upstream promoter of TPD52 In summary, these findings suggest that dysregulation of TPD52 by genomic amplification and androgen induction may play a role in prostate cancer progression

PKC412 inhibits the zinc finger 198-fibroblast growth factor receptor 1 fusion tyrosine kinase and is active in treatment of stem cell myeloproliferative disorder.

Abstract: Human stem cell leukemia-lymphoma syndrome usually presents itself as a myeloproliferative disorder (MPD) that evolves to acute myeloid leukemia and/or lymphoma. The syndrome associated with t(8;13)(p11;q12) results in expression of the ZNF198-fibroblast growth factor receptor (FGFR) 1 fusion tyrosine kinase. Current empirically derived cytotoxic chemotherapy is inadequate for treatment of this disease. We hypothesized that small-molecule inhibitors of the ZNF198-FGFR1 fusion would have therapeutic efficacy. We characterized the transforming activity of ZNF198-FGFR1 in hematopoietic cells in vitro and in vivo. Expression of ZNF198-FGFR1 in primary murine hematopoietic cells caused a myeloproliferative syndrome in mice that recapitulated the human MPD phenotype. Transformation in these assays, and activation of the downstream effector molecules PLC-γ, STAT5, and phosphatidylinositol 3-kinase/AKT, required the proline-rich domains, but not the ZNF domains, of ZNF198. A small-molecule tyrosine kinase inhibitor, PKC412 (N-benzoyl-staurosporine) effectively inhibited ZNF198-FGFR1 tyrosine kinase activity and activation of downstream effector pathways, and inhibited proliferation of ZNF198-FGFR1 transformed Ba/F3 cells. Furthermore, treatment with PKC412 resulted in statistically significant prolongation of survival in the murine model of ZNF198-FGFR1-induced MPD. Based in part on these data, PKC412 was administered to a patient with t(8;13)(p11;q12) and was efficacious in treatment of progressive myeloproliferative disorder with organomegaly. Therefore, PKC412 may be a useful therapy for treatment of human stem cell leukemia-lymphoma syndrome.

Gastrointestinal stromal tumors (GISTs) with KIT and PDGFRA mutations have distinct gene expression profiles

Abstract: Most GISTs require oncogenic activation of the KIT or PDGFRA receptor tyrosine kinase proteins, and the genomic mechanisms of oncogene activation are heterogeneous. Notably, the kinase mutation type correlates with both tumor biology and imatinib response. For example, GISTs with KIT exon 11 mutations are typically gastric and have excellent imatinib response, whereas those with KIT exon 9 mutations generally arise in the small bowel and are less responsive to imatinib. To identify genes that might contribute to these biological differences, we carried out gene expression profiling of 26 GISTs with known KIT and PDGFRA mutational status. Expression differences were then evaluated further by RNA in situ hybridization, immunohistochemistry, and immunoblotting. Unsupervised hierarchical clustering grouped tumors with similar mutations together, but the distinction between the different groups was not absolute. Differentially expressed genes included ezrin, p70S6K, and PKCs, which are known to have key roles in KIT or PDGFRA signaling, and which might therefore contribute to the distinctive clinicopathological features in GISTs with different mutation types. These gene products could serve as highly selective therapeutic targets in GISTs containing the KIT or PDGFRA mutational types with which they are associated.

Studies of acid exposure immediately above the gastro-oesophageal squamocolumnar junction: evidence of short segment reflux

Abstract: Background and aims: Oesophageal pH is conventionally recorded from a point 5 cm above the lower oesophageal sphincter. However, the mucosal changes of reflux oesophagitis and intestinal metaplasia tend to affect the segment of oesophagus distal to this and close to the squamocolumnar junction. This study set out to investigate oesophageal acid exposure of squamous mucosa close to the squamocolumnar junction. Methods: Dual channel 24 hour pH monitoring was carried out in 11 patients with endoscopy negative dyspepsia and no evidence of gastro-oesophageal reflux by conventional oesophageal pH metry. Oesophageal pH was recorded from electrodes positioned 5 mm and 55 mm proximal to the squamocolumnar junction. A novel technique was developed using metal clips to secure the pH catheter to the oesophageal mucosa and maintain these electrode positions. Oesophageal manometry indicated that the distal electrode was within the high pressure zone of the lower oesophageal sphincter. Results: We found that 24 hour oesophageal acid exposure (per cent time pH v 1.8%; p v 2.3%) and supine (10.5% v 1.3%) positions, as well as during preprandial (14.2% v 1.6%) and postprandial (21.8% v 2.8%) periods (p v 33; p Conclusions: The squamous mucosa of the most distal oesophagus is exposed to substantial acidic reflux, even in patients without evidence of conventional reflux disease. This short segment reflux may explain the high incidence of metaplasia and neoplasia at the gastro-oesophageal junction.

Protein Kinase C θ (PKCθ) Expression and Constitutive Activation in Gastrointestinal Stromal Tumors (GISTs)

Abstract: KIT expression is a key diagnostic feature of gastrointestinal stromal tumors (GISTs), and virtually all of the GISTs express oncogenic forms of the KIT or PDGFRA receptor tyrosine kinase proteins, which serve as therapeutic targets of imatinib mesylate (Gleevec; Novartis, Basel, Switzerland) However, KIT expression can be low in PDGFRA-mutant GISTs, increasing the likelihood of misdiagnosis as other types of sarcoma We report that the signaling intermediate protein kinase C θ (PKCθ) is a diagnostic marker in GISTs, including those that lack KIT expression and/or contain PDGFRA mutations PKCθ is strongly activated in most GISTs and hence may serve, along with KIT/PDGFRA, as a novel therapeutic target

Activation of the GLI Oncogene through Fusion with the beta-Actin Gene (ACTB) in a Group of Distinctive Pericytic Neoplasms: Pericytoma with t(7;12).

Abstract: Activation of the GLI oncogene is an important step in the sonic hedgehog signaling pathway, and leads to, eg, tissue-specific cell proliferation during embryogenesis. GLI activity in adult tissues is restricted, but has been identified in various neoplasms, as a result of mutations in the PTCH (patched) or SMOH (smoothened) genes, encoding components of the sonic hedgehog pathway, or by amplification of GLI. Herein, we present a new mechanism of GLI activation through fusion with the β-actin gene (ACTB) in five histologically distinctive soft tissue tumors showing a t(7;12)(p21-22;q13-15) and a pericytic phenotype. Each was composed of a perivascular proliferation of monomorphic short spindle cells that stained positively for smooth muscle actin and laminin and that showed pericytic features by electron microscopy. To date, with a median follow-up of 24 months, none has behaved in an aggressive manner. Molecular genetic analysis showed that the translocation in all cases resulted in a fusion transcript including the 5′-part of ACTB and the 3′-part of GLI. The DNA-binding zinc finger domains of GLI were retained in the fusion transcripts and it is likely that the replacement of the promoter region of GLI with that of the ubiquitously expressed ACTB gene leads to deregulation of GLI expression and its downstream target genes.

SU11248, a multi-targeted tyrosine kinase inhibitor, can overcome imatinib (IM) resistance caused by diverse genomic mechanisms in patients (pts) with metastatic gastrointestinal stromal tumor (GIST)

Abstract: 3001 Background: Resistance to Imatinib mesylate (IM) following initial tumor regression and disease control in GIST is increasingly recognized as an unmet medical need. IM resistance can be correlated with the appearance of secondary mutations in the KIT or PDGFRA tyrosine kinases in GIST lesions refractory to IM; activation of alternative signaling pathways and different structural biology of the new mutant kinases contribute to emergence of IM-resistant GIST clones. Methods: Phase I/II clinical trial of SU11248 in pts with progressing IM-resistant GIST. Tumor biopsies were obtained to define the mutational status of the KIT and PDGFRA kinases by dHPLC and sequencing assays. Results: 98 pts with progressive GIST have been enrolled in this ongoing study; with tumor response data available in 48 pts and GIST genotype determined in 41. The phase II regimen chosen was SU11248 50 mg orally once daily for 4 weeks, followed by a 2 week period off drug in each 6 wk cycle. SU11248 therapy induced clinical benefi...

Biology of gastrointestinal stromal tumors: KIT mutations and beyond.

Abstract: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the digestive tract. Aspects of the morphology and immunophenotype in GISTs resemble those in the interstitial cells of Cajal (ICC), which are a specialized cell type responsible for coordinating peristaltic activity throughout the gastrointestinal tract. Therefore, it is possible that GISTs result from transformation of nonneoplastic progenitor cells that would normally differentiate towards an ICC endpoint. Activation of the KIT receptor tyrosine kinase is required for differentiation and proliferation of nonneoplastic ICC, and oncogenic KIT mutations are a crucial event in the development of most GISTs. These mutations can involve either the extracellular or intracellular domains of the KIT receptor, giving rise to conformational changes that enable constitutive, ligand-independent, activation of the KIT protein. Oncogenic KIT activation leads to phosphorylation of various substrate proteins and, in turn, to activation of signal transduction cascades regulating cell proliferation, apoptosis, chemotaxis, and adhesion. Recently, a small molecule tyrosine kinase inhibitor (STI571, imatinib mesylate, Gleevec) directed against the enzymatic (kinase) domain of the KIT protein was found to produce dramatic clinical responses as monotherapy for metastatic GISTs. This review focuses on the biological and molecular genetic principles of GISTs, and particularly the role of mutant KIT as a therapeutic target.

Cavernous sinus and leptomeningeal metastases arising from a squamous cell carcinoma of the face: case report.

Abstract: Objective and importance Invasion of trigeminal and facial perineural spaces is a recognized complication of cutaneous malignancies. Centripetal spread along the trigeminal nerve axis and into the cavernous sinus and the gasserian ganglion is rare. Metastasis to the leptomeninges and cauda equina has not been reported. We report a unique case of perineural spread and central dissemination from an epithelial squamous cell carcinoma (SCC) associated with a tumor biomarker. Clinical presentation After excision of multiple cutaneous SCCs and basal cell carcinomas of the head and neck, a 70-year-old male patient developed successive, right-side, V1 and V2 trigeminal neuropathies and complete right cavernous sinus syndrome during a 5-year period. Concurrently, the right face became paralyzed. Left facial paresis developed during the latter half of this period. Two months before admission, subacute left lower-extremity radicular weakness resulted in falls. Serial magnetic resonance imaging scans obtained in the previous 4 years were unrevealing. At the time of admission, enhancing masses were found in the 1) right cavernous sinus and dura, foramina ovale and rotundum, and Meckel's cave, 2) right subtemporal region and orbital rectus muscles, and 3) cauda equina. Cerebrospinal fluid analysis demonstrated mild pleocytosis and rare carcinoma cells. Intervention Biopsy of the right cavernous sinus mass confirmed moderately differentiated, metastatic SCC. Immunohistochemical staining and fluorescence in situ hybridization revealed epidermal growth factor receptor overexpression and genomic amplification. Conclusion The indolent progression of cranial nerve palsy among patients with resected cutaneous SCCs of the head and neck must raise clinical suspicion of perineural spread, even in the absence of radiological changes. Biomarkers predicting aggressive SCC behavior, illustrated here by epidermal growth factor receptor amplification and central invasion, have the potential to guide early therapy.

Clonal evolution of resistance to imatinib (IM) in patients (pts) with gastrointestinal stromal tumor (GIST): molecular and radiologic evaluation of new lesions

Abstract: 3010 Background: Resistance to IM is emerging as a clinical challenge in pts with metastatic GIST following durable benefit and response. Novel patterns of progression have been noted in GIST pts, and we have explored the molecular and radiologic patterns of IM-refractory disease to supplement existing conventional criteria. Methods: Pts with metastatic GIST treated with IM were followed with serial CT/MRI and 18FDG-PET scans. Where feasible, biopsies were performed to document disease progression. Results: 89 pts were followed for a median of 39 months (m). 42/89 pts eventually developed progressive disease (PD, SWOG criteria) following partial (n=34) or minor (n=8) response (25–49% bidimensional decrease). A unique “nodule within a mass” pattern was seen in 22/42 pts, thought to represent emergence of a clone resistant to IM. This was defined as a new enhancing nodular focus enclosed within a pre-existing, non- or hypo-enhancing tumor mass that previously responded to IM. Nodules arose prior to developm...

Gastrointestinal stromal tumours: etiology, pathology and clinical management.

Abstract: Investigation of the regulation of cell growth, differentiation and death by signalling pathways has led to a greater understanding of how alterations in these pathways play a critical role in the development of some cancers, and has opened new opportunities for their treatment. In the present review, results with the prototype drug of this class, imatinib (Gleevec, Glivec [formerly STI571]; Novartis, Switzerland), in metastatic gastrointestinal stromal tumours are presented. The present review originated from a conference of the authors held in Montreal, Quebec in June 2003, under the sponsorship of Novartis.

Induction of TRAIL and XAF-1 and inhibition of p-Akt and c-Kit expression by interferons (IFNs) is associated with apoptosis in GIST cells

Abstract: 9027 Background: Since few complete responses occur and a subset of patients do not respond at all, additional biologically targeted interventions are needed for patients with metastatic GIST. Among pleiotropic actions of IFNs are inhibition of cell proliferation and induction of apoptosis-effects we postulated might occur in cell lines derived from GIST. Methods: KIT-dependent GIST882 cells were treated with IFN-α2 or IFN-β at concentrations of 10–500 units and antiproliferative effects (cell counts) and apoptosis (flow cytometry) assessed at 3 and 7 days. Gene induction and signal pathway components were assessed by quantitative RT-PCR and western blot. Results: At 10 units of IFN-β cell counts decreased 70% and at 50 units 90%; IFN-α2 decreased cell counts 10% (10 units) and 75% (50 units). Imatinib mesylate (1μM) resulted in 75% inhibition. Apoptosis was assessed at 3 and 7 d with increasing doses of IFNs. A dose and time-related increase in apoptosis occurred with 100 units of IFN-β resulting in >50%...

APPENDIX 1D Reporting of Diagnostic Cytogenetic Results

Abstract: This appendix, developed by the staff at the Clinical Cytogenetics Laboratory at the Brigham and Women's Hospital, includes a comprehensive list of current “macros” or standardized statements used to facilitate reporting of cytogenetic results. These are provided as a reference for other laboratories. The statements are organized under the general categories of constitutional or acquired abnormalities and subdivided into analysis type (GTG-banding or FISH). Multi-specimen usage macros are included that can be applied to two or more specimen types. Curr. Protoc. Hum. Genet. 67:A.1D.1-A.1D.24 © 2010 by John Wiley & Sons, Inc. Keywords: clinical cytogenetics; diagnostic; reporting; test results