Serum biomarkers for neurofibromatosis type 1 and early detection of malignant peripheral nerve-sheath tumors
- Su-Jin Park1,
- Birgit Sawitzki2,
- Lan Kluwe3,
- Victor F Mautner†3,
- Nikola Holtkamp†1 and
- Andreas Kurtz†1, 4Email author
© Park et al.; licensee BioMed Central Ltd. 2013
Received: 27 July 2012
Accepted: 8 March 2013
Published: 23 April 2013
Neurofibromatosis type 1 (NF1) is a hereditary tumor syndrome characterized by the development of benign nerve-sheath tumors, which transform to malignant peripheral nerve-sheath tumors (MPNST) in about 8 to 13% of patients with NF1. MPNST are invasive sarcomas with extremely poor prognosis, and their development may correlate with internal tumor load of patients with NF1. Because early identification of patients with NF1 at risk for developing MPNST should improve their clinical outcome, the aim of this study was to identify serum biomarkers for tumor progression in NF1, and to analyze their correlation with tumor type and internal tumor load.
We selected candidate biomarkers for NF1 by manually mining published data sources, and conducted a systematic screen of 56 candidate serum biomarkers using customized antibody arrays. Serum from 104 patients with NF1 with and without MPNST, and from 41 healthy control subjects, was analyzed. Statistical analysis was performed using the non-parametric Mann–Whitney U-test, followed by Bonferroni correction.
Our analysis identified four markers (epidermal growth factor receptor, interferon-γ, interleukin-6, and tumor necrosis factor-α) for which significantly different serum concentrations were seen in patients with NF1 compared with healthy controls. Two markers (insulin-like growth factor binding protein 1 (IGFBP1) and regulated upon activation, normal T-cell expressed and secreted (RANTES)) showed significantly higher concentrations in patients with NF1 and MPNST compared with patients with NF1 without MPNST. A correlation with internal tumor load was found for IGFBP1.
Our study identified two serum markers with potential for early detection of patients with NF1 at risk for developing MPNST, and four markers that could distinguish between patients with NF1 and healthy subjects. Such markers may be useful as diagnostic tools to support the diagnosis of NF1 and for timely identification of MPNST. Moreover, the data suggest that there is a systemic increase in inflammatory cytokines independently of tumor load in patients with NF1.
KeywordsNeurofibromatosis type 1 Serum biomarker Antibody array Cytokines Malignant peripheral nerve-sheath tumor
Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor syndrome, with an estimated incidence at birth of 1 in 2500  and complete penetrance. NF1 is caused by mutations in the NF1 gene [2, 3], coding for the tumor-suppressor protein neurofibromin, which acts as a Ras-negative regulator via its Ras-GTPase activating protein (GAP) domain. Monoallelic and biallelic loss of NF1 leads to increased Ras activity in affected cells.
Among the defining features of NF1 is the development of benign peripheral nerve-sheath tumors, which can arise at virtually any site in the body. Whereas cutaneous neurofibromas (CNF) are mostly visible and palpable, subcutaneous neurofibromas, internal plexiform neurofibromas (PNF) and malignant peripheral nerve-sheath tumors (MPNST) are difficult to detect, quantify, or monitor .
MPNST are the major cause for the reduced life span of patients with NF1, and they will lead to death if not detected early and treated in time. The primary forms of treatment are selective resection of benign PNF, and radical surgical resection of MPNST [5–8]. However, the invasive growth pattern of MPNST frequently prohibits complete tumor removal, especially when diagnosed late in their development. Moreover, although chemotherapy and radiotherapy may delay recurrence, they have little effect on long-term survival [7, 9].
The lifetime risk of MPNST for patients with NF1 patients has been estimated to be about 8 to 13% and thus is more than 1000 times higher for these patients than for the general population. Moreover, many patients with NF1 develop MPNST at the unusually young age of around 30 years [10, 11], compared with the median age of diagnosis of 62 years in the general population . Because MPNST develop by malignant progression of pre-existing PNF, the risk to develop an MPNST increases to almost 50% in patients with NF1 and PNF [12, 13].
It is possible to detect dermal and superficial neurofibromas directly by optical or ultrasonography methods , whereas PNF and MPNST are often diagnosed only after clinical symptoms occur. Systematic analysis of the internal tumor load of patients with NF1 by whole-body magnetic resonance imaging (MRI) suggests an association between the risk for MPNST development and internal PNF tumor load . However, these imaging techniques are not applicable as a routine screening tool. The search for surrogate biomarkers for timely identification of patients at risk for malignant transformation has mostly been based on the assumption that overexpression of proteins in PNF and MPNST subsequently leads to increased systemic concentrations [16–19]. Among such factors, serum levels for midkine and for stem cell factor were found to be significantly increased in a cohort of 39 patients with NF1, although no correlation with tumor load or MPNST was found . Recently, we identified melanoma-inhibitory activity (MIA; also known as cartilage-derived retinoic acid-sensitive protein (CD-RAP)) as a marker for the internal tumor load in a cohort of 42 patients with NF1 . MIA was shown previously to be a biomarker for malignant neuroectotermal tumors . In another study, 92 genes encoding putative secreted proteins in neurofibromas and MPNST were analyzed for their potential as serum markers . Of these, only adrenomedullin (ADM) was confirmed as differentially expressed and increased in the serum of patients with NF1, and serum concentrations were found to be even higher in a small sample of patients with MPNST (n = 5).
Tumorigenesis in NF1 is strongly influenced by the haploinsufficient NF1+/− systemic environment, which may also promote invasion of PNF and MPNST by NF1+/− monocytes and mast cells [24–30]. Therefore, we included immunomodulating cytokines in the present screen for serum biomarkers, in addition to factors secreted by tumor cells in PNF and MPNST. Of the 56 candidate proteins analyzed, we identified four proteins with significantly altered serum concentrations in patients with NF1 compared with non-NF1 control subjects, but independently of tumor load. Two proteins were significantly increased in patients with MPNST, and one of these also correlated with internal tumor load.
The study was approved by the internal review board (Ethics Committee of the Ärztekammer Hamburg number OB-089/04) in compliance with the Declaration of Helsinki, and informed consent was obtained before sample collection.
Patients and serum collection
Serum samples from patients with NF1 were obtained from the Department of Maxillofacial Surgery (University Hospital Eppendorf, Hamburg, Germany). All patients with NF1 were clinically diagnosed according to published guidelines and criteria . Serum samples from healthy control subjects were obtained from the Institute of Medical Immunology (Charité - Universitätsmedizin Berlin) from anonymized leftover diagnostic samples. For detailed information on the patient cohorts, see Additional file 1. Venous blood (1 to 10 ml) was collected, then separated by centrifugation within 2 hours of collection, and serum samples were immediately frozen in aliquots and stored at −80°C until use. Fresh aliquots were used for each analysis.
Candidate marker selection
Customized human cytokine arrays (Quantibody; RayBiotech Inc., GA, USA) were used to determine serum protein concentrations. Analyses were performed in accordance with the manufacturer’s instructions. Imaging was performed using the accompanying software (Quantibody Array Testing Software; RayBiotech Inc.). Potential marker proteins were initially identified by screening of 30 candidate proteins using 60 NF1 sera (n = 27, n = 13, and n = 20, respectively, for patients with NF1 with PNF, with MPNST, and without tumors) and 20 control sera. Secondary screening was performed on the five proteins that showed significant differences in the pre-screening round (platelet-derived growth factor (PDGF)-BB, insulin-like growth factor binding protein (IGFBP)1, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-4, TNF-related apoptotic ligand (TRAIL)-R2), together with another set of 26 candidate proteins (see Additional file 2). In the second round, 104 NF1 sera and 41 control sera were screened. Altogether, 56 candidate proteins were screened, and 104 NF1 and 41 control sera were used. The candidate proteins were simultaneously scanned by multiplex detection in quadruplicate spots per array. Hence, all sera were analyzed in at least quadruplicates. A flowchart of the screening procedure is provided (Figure 1). Serum factors with significantly different levels between groups (with the exception of epidermal growth factor receptor (EGFR)) were verified in a limited subset of NF1 (n ≥ 11) and control (n ≥ 5) serum samples using ELISA for IGFBP1 (Abcam, Cambridge, UK), and cytometric bead array (CBA) (BD Bioscience, Heidelberg, Germany) for RANTES (regulated upon activation, normal T-cell expressed and secreted), interferon (IFN)-γ, interleukin (IL)-6 and TNF-α. The analyses were performed in accordance with the manufacturers’ instructions. Capture beads were analyzed on a flow cytometer (FACSCalibur, BD Biosciences, Heidelberg, Germany), and flow-cytometry data were evaluated with FCAP Array analysis software (Soft Flow Inc., MN, USA) (see Additional file 3).
Serum levels of the candidate markers in the NF1 patient group and control group were analyzed with respect to median levels and interquartile ranges. To verify all data for normal distribution, the Kolmogorov-Smirnov test was used. Stratified patient groups were compared using the Mann–Whitney U-test for continuous non-parametric variables. For assessing the discriminatory power of individual markers, the receiver operating characteristic (ROC) curve and area under the curve (AUC) were calculated. For significance testing, the non-parametric Mann–Whitney U-test followed by Bonferroni correction was used. Two-tailed tests were used for all analyses. P<0.05 was considered significant. Statistical analysis was performed using SPSS version 18 software (SPSS, Inc., IL, USA) and GraphPad Prism software (version 5.0 GraphPad Software Inc., CA, USA).
Results and discussion
Characteristics of patient cohorts recruited for the study
w/o PNF w/o MPNST
with PNF w/o MPNST
mean age in years
47 (range 24–66)
32 (range 14–48)
34 (range 15–63)
34 (range 16–62)
whole body MRI
Serum concentrations of all six candidate markers were independent of age and sex in the tested population (mean age was 46 and 32 years for the healthy controls and the NF1 group, respectively). This is important, as circulating levels of the inflammatory cytokines TNF-α and IL-6 may increase with age [36, 37].
A previous study using volumetric analysis of whole-body MRI data for patients with NF1 indicated a correlation between internal tumor load and risk for malignant transformation of PNF into MPNST . Therefore, we attempted to correlate the serum concentration of the six identified serum biomarkers with internal tumor load for the 87 patients with NF1 for which these data were available (see Additional file 1). Importantly, the serum concentrations of IGFBP1, but not of any of the other five markers, correlated with internal tumor load (Figure 3C).
This finding is in line with the correlation between IGFBP1 serum levels and presence of MPNST (Figure 3A), and further identifies IGFBP1 as a potential risk marker for malignant transformation. The data also suggest that increased cytokine levels in patients with NF1 are independent of tumor load. Rather, these results imply that systemic NF1 haploinsufficiency triggers a permanent and systemic inflammatory status in patients with NF1, which is reflected by a significant increase in IFN-γ, TNF-α and IL-6 .
Protein array data were confirmed in a small subgroup by CBA and ELISA (see Additional file 3) for IFN-γ, TNF-α, IL-6, IGFBP1 and RANTES. We did not reassess the level of EGFR because of its comparably lower AUC.
Overview on serum marker features at 90% sensitivity
cut off (ng/ml):
In patients with MPNST, the AUC of IGFBP1 (0.77) was larger than that of RANTES (0.65) (Figure 4). RANTES is an inflammatory chemokine known to mediate chemotactic activity in immune cells such as T cells and monocytes . RANTES was also shown to be expressed by breast carcinomas , and correlated with a more advanced stage of disease, suggesting a role for cancer progression. Increased serum levels of RANTES and IGFBP1 may be the result of increased secretion by the tumor cells themselves, or by immune cells in response to the neoplastic process, or by both mechanisms.
IGFBP1 binds IGF-I and IGF-II, and prolongs their half-life. Plasma levels of IGFBP1 are regulated by hormones outside of the growth-hormone axis, including insulin, glucagon, and cortisol [42, 43]. An inverse correlation has previously been indicated between IGFBP1 levels and carcinogenesis [44, 45]. The expression of IGF-I and growth-hormone receptors in PNF and MPNST in patients with NF1, and the correlation between IGF-I receptor levels and the increased mitosis index of PNFs, suggest sensitivity of these tumors to IGFBP1-regulated factors [10, 46]. Taken together, IGFBP1 may modulate IGF access to PNF and MPNST, although this mechanism still needs to be elucidated.
The reasons for the reduced circulating EGFR levels that we detected in patients with NF1 are unclear. A possible functional explanation may be enhanced survival of cells that retain their EGFR on the cell surface, providing readiness for EGF signaling . Similarly, EGF signaling has been shown to enhance tumorigenesis in NF1 animal models, and NF1-derived Schwann cells and fibroblasts are highly sensitive to EGF . Hence, it seems that retaining the EGFR on the cell surface leads to reduced circulation of soluble EGFR, and provides an environment that promotes tumorigenesis, as seen in patients with NF1.
Recently, two studies identified MIA and ADM as potential NF1 tumor markers in cohorts of 42 and 32 patients, respectively [21, 23]. There was also a trend towards correlation between ADM and MPNST, although the MPNST group was too small to show significance (n = 5). MIA concentration was particularly high in patients with NF1 with either PNF or large numbers of neurofibromas, and correlated with internal tumor burden. Both of these factors seem to be related to tumor burden in NF1, although induction as a result of changed systemic environment due to haploinsufficiency cannot be excluded. It would be intriguing to investigate further what role, if any, a systemic inflammatory environment may play in the early stages of tumorigenesis in patients with NF1.
Our study encompasses the largest cohort of patients with NF1 (n = 104) screened to date for potential serum markers in this rare genetic cancer syndrome. We identified four potential biomarkers, which may assist in the diagnosis of NF1, and two further markers (IGFBP1 and RANTES) that correlate with the presence of MPNST. Intriguingly, IGFBP1 also seems to correlate with internal tumor burden, and thus may indicate increased risk for malignant transformation in patients with NF1. Furthermore, our data reveal a systemic pro-inflammatory profile in patients with NF1, which is probably caused by NF1 haploinsufficiency. Serum biomarkers that could aid in the early detection of malignant progression would be extremely helpful because therapeutic interventions could be initiated before further spread of the tumor or development of metastasis takes place. Both the current and previous data are very promising for further validation of the data in even larger cohorts. It would be intriguing to further investigate what, if any, role a systemic inflammatory environment may play in the early stages of tumorigenesis in patients with NF1. Multicenter studies in larger cohorts will be necessary to validate the identified markers, and to elucidate a possible role of inflammatory cytokines in tumorigenesis.
Area under the curve
Cytometric bead array
Epidermal growth factor receptor
enzyme-linked immunosorbent assay (ELISA)
Insulin-like growth factors
Insulin-like growth factor binding protein 1
Macrophage inflammatory protein-4
Malignant peripheral nerve-sheath tumors
Magnetic resonance imaging
Magnetic resonance tomography
Neurofibromatosis type 1
Platelet-derived growth factor-BB
Regulated upon activation, normal T-cell expressed and secreted
Receiver operating characteristic
Tumor necrosis factor-α
TNF-related apoptosis inducing ligand-R2.
This work was supported by the Deutsche Krebshilfe (grant 109713) to VM, the Bundesministerium für Bildung und Forschung (BMBF) (grant 01GM0840) to AK, NH, and VM, and by the Rudolf-Bartling Siftung Project II/85 and a US Medical Research grant NF043115 (W81XWH-05-1-0201) to AK and VM. We thank Petra Reinke for her continued support of the project, and Jessica Knoblauch for her excellent technical assistance.
- Huson SM, Compston DA, Clark P: A genetic study of von Recklinghausen neurofibromatosis in south east Wales: I. Prevalence, fitness, mutation rate, and effect of parental transmission on severity. J Med Genet. 1989, 26: 704-711. 10.1136/jmg.26.11.704.View ArticlePubMedPubMed CentralGoogle Scholar
- Friedman JM, Gutmann DH, Maccollin M: Neurofibromatosis. Phenotype, Natural History and Pathogenesis. 1999, Balltimore: The Johns Hopkins University Press, 110-118.Google Scholar
- Geller M, Bonalumi Filho A: Neurofibromatose: Clínica, Genética e Terapêutica. 2004, Rio de Janeiro: Guanabara KooganGoogle Scholar
- Mautner VF, Hartmann M, Kluwe L, Friedrich RE, Fünsterer C: MRI growth patterns of plexiform neurofibromas in patients with neurofibromatosis type 1. Neuroradiology. 2006, 48: 160-165. 10.1007/s00234-005-0033-4.View ArticlePubMedGoogle Scholar
- Ducatman B, Scheithauer B, Piepgras D: Malignant peripheral nerve sheath tumors: a clinicopathologic study of 120 cases. Cancer. 1986, 57: 2006-2021. 10.1002/1097-0142(19860515)57:10<2006::AID-CNCR2820571022>3.0.CO;2-6.View ArticlePubMedGoogle Scholar
- Collin C, Godbold J, Hajdu S: Localized extremity soft tissue sarcoma: an analysis of factors affecting survival. J Clin Oncol. 1987, 5: 601-612.PubMedGoogle Scholar
- Ferner RE, Gutmann DH: International consensus statement on malignant peripheral nerve sheath tumors in neurofibromatosis 1. Cancer Res. 2002, 62: 1573-1577.PubMedGoogle Scholar
- Packer RJ, Gutmann DH, Rubenstein A, Viskochil D, Zimmerman RA, Vezina G, Small J, Korf B: Plexiform neurofibromas in NF1: toward biologic-based therapy. Neurology. 2002, 58: 1461-1470. 10.1212/WNL.58.10.1461.View ArticlePubMedGoogle Scholar
- Wanebo J, Malik J, VandenBerg S, Wanebo H, Driessen N, Persing J: Malignant peripheral nerve sheath tumors: a clinicopathological study of 28 cases. Cancer. 1993, 71: 1247-1253. 10.1002/1097-0142(19930215)71:4<1247::AID-CNCR2820710413>3.0.CO;2-S.View ArticlePubMedGoogle Scholar
- Friedrich RE, Keiner D, Hagel C: Expression of insulin-like growth-factor-1 receptor (IGF-1R) in peripheral nerve sheath tumors in neurofibromatosis type 1. Anticancer Res. 2007, 27: 2085-2090.PubMedGoogle Scholar
- Rasmussen SA, Yang Q, Friedman JM: Mortality in neurofibromatosis 1: an analysis using U.S. death certificates. Am J Hum Genet. 2001, 68: 1110-1118. 10.1086/320121.View ArticlePubMedPubMed CentralGoogle Scholar
- Evans DG, Baser ME, McGaughran J, Sharif S, Howard E, Moran A: Malignant peripheral nerve sheath tumours in neurofibromatosis 1. J Med Genet. 2002, 39: 311-314. 10.1136/jmg.39.5.311.View ArticlePubMedPubMed CentralGoogle Scholar
- Ward BA, Gutmann DH: Neurofibromatosis 1: from lab bench to clinic. Pediatr Neurol. 2005, 32: 221-228. 10.1016/j.pediatrneurol.2004.11.002.View ArticlePubMedGoogle Scholar
- Algermissen B, Hermes B, Henz BM, Müller U, Berlien HP: Laser-induced weal and flare reactions: clinical aspects and pharmacological modulation. Br J Dermatol. 2002, 146: 863-868. 10.1046/j.1365-2133.2002.04723.x.View ArticlePubMedGoogle Scholar
- Plotkin SR, Bredella MA, Cai W, Kassarjian A, Harris GJ, Esparza S, Merker VL, Munn LL, Muzikansky A, Askenazi M, Nguyen R, Wenzel R, Mautner VF: Quantitative assessment of whole-body tumor burden in adult patients with neurofibromatosis. PLoS One. 2012, 7: e35711-10.1371/journal.pone.0035711.View ArticlePubMedPubMed CentralGoogle Scholar
- Kurtz A, Martuza RL: Antiangiogenesis in neurofibromatosis 1. J Child Neurol. 2002, 17: 578-584. 10.1177/088307380201700807. discussion 602–4, 646–51View ArticlePubMedGoogle Scholar
- Lamba M, Veinot JP, Acharya V: Vascular and valvular involvement by neurofibromatosis. Pathology. 2002, 34: 380-383.View ArticlePubMedGoogle Scholar
- Hamilton SJ, Friedman JM: Insights into the pathogenesis of neurofibromatosis 1 vasculopathy. Clin Genet. 2000, 58: 341-344.View ArticlePubMedGoogle Scholar
- Arbiser JL, Flynn E, Barnhill RL: Analysis of vascularity of human neurofibromas. J Am Acad Dermatol. 1998, 38: 950-954. 10.1016/S0190-9622(98)70158-6.View ArticlePubMedGoogle Scholar
- Mashour GA, Hernáiz P, Hartmann M, Mashour S, Zhang T, Scharf B, Felderhoff-Müse U, Sakuma S, Friedrich RE, Martuza RL, Mautner VF, Kurtz A: Circulating growth factor levels are associated with tumorigenesis in neurofibromatosis type 1. Clin Canc Res. 2004, 10: 5677-5683. 10.1158/1078-0432.CCR-03-0769.View ArticleGoogle Scholar
- Kolanczyk M, Mautner V, Kossler N, Nguyen R, Kühnisch J, Zemojtel T, Jamsheer A, Wegener E, Thurisch B, Tinschert S, Holtkamp N, Park SJ, Birch P, Kendler D, Harder A, Mundlos S, Kluwe L: MIA is a potential biomarker for tumour load in neurofibromatosis type 1. BMC Med. 2011, 9: 82-10.1186/1741-7015-9-82.View ArticlePubMedPubMed CentralGoogle Scholar
- Hau P, Apfel R, Wiese P, Tschertner I, Blesch A, Bogdahn U: Melanoma-inhibiting activity (MIA/CD-RAP) is expressed in a variety of malignant tumors of mainly neuroectodermal origin. Anticancer Res. 2002, 22: 577-583.PubMedGoogle Scholar
- Hummel TR, Jessen WJ, Miller SJ, Kluwe L, Mautner VF, Wallace MR, Lázaro C, Page GP, Worley PF, Aronow BJ, Schorry EK, Ratner N: Gene expression analysis identifies potential biomarkers of neurofibromatosis type 1 including adrenomedullin. Clin Cancer Res. 2010, 16: 5048-5057. 10.1158/1078-0432.CCR-10-0613.View ArticlePubMedPubMed CentralGoogle Scholar
- Staser K, Yang FC, Clapp DW: Pathogenesis of plexiform neurofibroma: tumor-stromal/hematopoietic interactions in tumor progression. Annu Rev Pathol. 2012, 7: 469-495. 10.1146/annurev-pathol-011811-132441.View ArticlePubMedGoogle Scholar
- Le LQ, Parada LF: Tumor microenvironment and neurofibromatosis type I: connecting the GAPs. Oncogene. 2007, 26: 4609-4616. 10.1038/sj.onc.1210261.View ArticlePubMedPubMed CentralGoogle Scholar
- Brossier NM, Carroll SL: Genetically engineered mouse models shed new light on the pathogenesis of neurofibromatosis type I-related neoplasms of the peripheral nervous system. Brain Res Bull. 2012, 88: 58-71. 10.1016/j.brainresbull.2011.08.005.View ArticlePubMedGoogle Scholar
- Yang FC, Ingram DA, Chen S, Hingtgen CM, Ratner N, Monk KR, Clegg T, White H, Mead L, Wenning MJ, Williams DA, Kapur R, Atkinson SJ, Clapp DW: Neurofibromin-deficient Schwann cells secrete a potent migratory stimulus for Nf1+/− mast cells. J Clin Invest. 2003, 112: 1851-1861.View ArticlePubMedGoogle Scholar
- Yang FC, Chen S, Clegg T, Li X, Morgan T, Estwick SA, Yuan J, Khalaf W, Burgin S, Travers J, Parada LF, Ingram DA, Clapp DW: Nf1+/− mast cells induce neurofibroma like phenotypes through secreted TGF-beta signaling. Hum Mol Genet. 2006, 15: 2421-2437. 10.1093/hmg/ddl165.View ArticlePubMedPubMed CentralGoogle Scholar
- Theoharides TC, Conti P: Mast cells: the Jekyll and Hyde of tumor growth. Trends Immunol. 2004, 25: 235-241. 10.1016/j.it.2004.02.013.View ArticlePubMedGoogle Scholar
- Yang FC, Ingram DA, Chen S, Zhu Y, Yuan J, Li X, Yang X, Knowles S, Horn W, Li Y, Zhang S, Yang Y, Vakili ST, Yu M, Burns D, Robertson K, Hutchins G, Parada LF, Clapp DW: Nf1-dependent tumors require a microenvironment containing Nf1+/− and c-kit-dependent bone marrow. Cell. 2008, 135: 437-448. 10.1016/j.cell.2008.08.041.View ArticlePubMedPubMed CentralGoogle Scholar
- Ferner RE, Huson SM, Thomas N, Moss C, Willshaw H, Evans DG, Upadhyaya M, Towers R, Gleeson M, Steiger C, Kirby A: Guidelines for the diagnosis and management of individuals with neurofibromatosis 1. J Med Genet. 2007, 44: 81-88. 10.1136/jmg.2007.049122.View ArticlePubMedGoogle Scholar
- Ashburner M, Ball CA, Blake JA, Botstein D, Butler H, Cherry JM, Davis AP, Dolinski K, Dwight SS, Eppig JT, Harris MA, Hill DP, Issel-Tarver L, Kasarskis A, Lewis S, Matese JC, Richardson JE, Ringwald M, Rubin GM, Sherlock G: Gene ontology: tool for the unification of biology. The gene ontology consortium. Nat Genet. 2000, 25: 25-29. 10.1038/75556.View ArticlePubMedPubMed CentralGoogle Scholar
- Rebhan M, Chalifa-Caspi V, Prilusky J, Lancet D: GeneCards: integrating information about genes, proteins and diseases. Trends Genet. 1997, 13: 163-10.1016/S0168-9525(97)01103-7.View ArticlePubMedGoogle Scholar
- Yoshida Y, Adachi K, Yamamoto O: Local mast cell histamine and plasma histamine levels in neurofibromatosis type 1. Acta Derm Venereol. 2010, 90: 637-639. 10.2340/00015555-0938.View ArticlePubMedGoogle Scholar
- Lasater EA, Li F, Bessler WK, Estes ML, Vemula S, Hingtgen CM, Dinauer MC, Kapur R, Conway SJ, Ingram DA: Genetic and cellular evidence of vascular inflammation in neurofibromin-deficient mice and humans. J Clin Invest. 2010, 120: 859-870. 10.1172/JCI41443.View ArticlePubMedPubMed CentralGoogle Scholar
- Kim HO, Kim HS, Youn JC, Shin EC, Park S: Serum cytokine profiles in healthy young and elderly population assessed using multiplexed bead-based immunoassays. J Transl Med. 2011, 9: 113-10.1186/1479-5876-9-113.View ArticlePubMedPubMed CentralGoogle Scholar
- Krabbe KS, Pedersen M, Bruunsgaard H: Inflammatory mediators in the elderly. Exp Gerontol. 2004, 39: 687-699. 10.1016/j.exger.2004.01.009.View ArticlePubMedGoogle Scholar
- Nowsheen S, Aziz K, Panayiotidis MI, Georgakilas AG: Molecular markers for cancer prognosis and treatment: Have we struck gold?. Cancer Lett. 2012, 327: 142-152. 10.1016/j.canlet.2011.11.022.View ArticlePubMedGoogle Scholar
- Baay M, Brouwer A, Pauwels P, Peeters M, Lardon F: Tumor cells and tumor-associated macrophages: secreted proteins as potential targets for therapy. Clin Dev Immunol. 2011, 2011: 565187.View ArticlePubMedPubMed CentralGoogle Scholar
- Schall TJ, Bacon K, Toy KJ, Goeddel DV: Selective attraction of monocytes and T lymphocytes of the memory phenotype by cytokine RANTES. Nature. 1990, 347: 669-671. 10.1038/347669a0.View ArticlePubMedGoogle Scholar
- Luboshits G, Shina S, Kaplan O, Engelberg S, Nass D, Lifshitz-Mercer B, Chaitchik S, Keydar I, Ben-Baruch A: Elevated expression of the CC chemokine regulated on activation, normal T cell expressed and secreted (RANTES) in advanced breast carcinoma. Cancer Res. 1999, 59: 4681-4687.PubMedGoogle Scholar
- Rajaram S, Baylink DJ, Mohan S: Insulin-like growth factor-binding proteins in serum and other biological fluids: regulation and functions. Endocr Rev. 1997, 18: 801-831. 10.1210/er.18.6.801.PubMedGoogle Scholar
- Giovannucci E: Nutrition, insulin, insulin-like growth factors and cancer. Horm Metab Res. 2003, 35: 694-704.View ArticlePubMedGoogle Scholar
- Wolpin BM, Meyerhardt JA, Chan AT, Ng K, Chan JA, Wu K, Pollak MN, Giovannucci EL, Fuchs CS: Insulin, the insulin-like growth factor axis, and mortality in patients with nonmetastatic colorectal cancer. J Clin Oncol. 2009, 27: 176-185. 10.1200/JCO.2008.17.9945.View ArticlePubMedPubMed CentralGoogle Scholar
- Tran TT, Medline A, Bruce WR: Insulin promotion of colon tumors in rats. Cancer Epidemiol Biomarkers Prev. 1996, 5: 1013-1015.PubMedGoogle Scholar
- Cunha KS, Barboza EP, Da Fonseca EC: Identification of growth hormone receptor in localised neurofibromas of patients with neurofibromatosis type 1. J Clin Pathol. 2003, 56: 758-763. 10.1136/jcp.56.10.758. J Neurooncol 2011; 102:71–80View ArticlePubMedPubMed CentralGoogle Scholar
- Rodrigues M, Blair H, Stockdale L, Griffith L, Wells A: Surface tethered epidermal growth factor protects proliferating and differentiating multipotential stromal cells from fasl induced apoptosis. Stem Cells. 2013, 31: 104-116. 10.1002/stem.1215.View ArticlePubMedPubMed CentralGoogle Scholar
- Williams JP, Wu J, Johansson G, Rizvi TA, Miller SC, Geiger H, Malik P, Li W, Mukouyama YS, Cancelas JA, Ratner N: Nf1 mutation expands an EGFR-dependent peripheral nerve progenitor that confers neurofibroma tumorigenic potential. Cell Stem Cell. 2008, 3: 658-669. 10.1016/j.stem.2008.10.003.View ArticlePubMedPubMed CentralGoogle Scholar
- Karube K, Nabeshima K, Ishiguro M, Harada M, Iwasaki H: cDNA microarray analysis of cancer associated gene expression profiles in malignant peripheral nerve sheath tumours. J Clin Pathol. 2006, 59: 160-165. 10.1136/jcp.2004.023598.View ArticlePubMedPubMed CentralGoogle Scholar
- Thomas SL, De Vries GH: Angiogenic expression profile of normal and neurofibromin-deficient human Schwann cells. Neurochem Res. 2007, 32: 1129-1141. 10.1007/s11064-007-9279-z.View ArticlePubMedGoogle Scholar
- Miller SJ, Li H, Rizvi TA, Huang Y, Johansson G, Bowersock J, Sidani A, Vitullo J, Vogel K, Parysek LM, DeClue JE, Ratner N: Brain lipid binding protein in axon-Schwann cell interactions and peripheral nerve tumorigenesis. Mol Cell Biol. 2003, 23: 2213-2224. 10.1128/MCB.23.6.2213-2224.2003.View ArticlePubMedPubMed CentralGoogle Scholar
- Lee PR, Cohen JE, Tendi EA, Farrer R, DE Vries GH, Becker KG, Fields RD: Transcriptional profiling in an MPNST-derived cell line and normal human Schwann cells. Neuron Glia Biol. 2004, 1: 135-147. 10.1017/S1740925X04000274.View ArticlePubMedPubMed CentralGoogle Scholar
- Bahuau M, Pelet A, Vidaud D, Lamireau T, LeBail B, Munnich A, Vidaud M, Lyonnet S, Lacombe D: GDNF as a candidate modifier in a type 1 neurofibromatosis (NF1) enteric phenotype. J Med Genet. 2001, 38: 638-643. 10.1136/jmg.38.9.638.View ArticlePubMedPubMed CentralGoogle Scholar
- Lévy P, Bièche I, Leroy K, Parfait B, Wechsler J, Laurendeau I, Wolkenstein P, Vidaud M, Vidaud D: Molecular profiles of neurofibromatosis type 1-associated plexiform neurofibromas: identification of a gene expression signature of poor prognosis. Clin Cancer Res. 2004, 10: 3763-3771. 10.1158/1078-0432.CCR-03-0712.View ArticlePubMedGoogle Scholar
- Nakayama J, Terao H: Gamma interferon directly inhibits the growth of neurofibroma cells in vitro. J Dermatol. 2002, 29: 556-561.View ArticlePubMedGoogle Scholar
- Tierney EP, Tulac S, Huang ST, Giudice LC: Activation of the protein kinase A pathway in human endometrial stromal cells reveals sequential categorical gene regulation. Physiol Genomics. 2003, 16: 47-66. 10.1152/physiolgenomics.00066.2003.View ArticlePubMedGoogle Scholar
- Tuskan RG, Tsang S, Sun Z, Baer J, Rozenblum E, Wu X, Munroe DJ, Reilly KM: Real-time PCR analysis of candidate imprinted genes on mouse chromosome 11 shows balanced expression from the maternal and paternal chromosomes and strain-specific variation in expression levels. Epigenetics. 2008, 3: 43-50. 10.4161/epi.3.1.5469.View ArticlePubMedGoogle Scholar
- Park JI, Powers JF, Tischler AS, Strock CJ, Ball DW, Nelkin BD: GDNF-induced leukemia inhibitory factor can mediate differentiation via the MEK/ERK pathway in pheochromocytoma cells derived from nf1-heterozygous knockout mice. Exp Cell Res. 2005, 303: 79-88.PubMedGoogle Scholar
- Muir D: Differences in proliferation and invasion by normal, transformed and NF1 Schwann cell cultures are influenced by matrix metalloproteinase expression. Clin Exp Metastasis. 1995, 13: 303-314. 10.1007/BF00133486.View ArticlePubMedGoogle Scholar
- Lévy P, Ripoche H, Laurendeau I, Lazar V, Ortonne N, Parfait B, Leroy K, Wechsler J, Salmon I, Wolkenstein P, Dessen P, Vidaud M, Vidaud D, Bièche I: Microarray-based identification of tenascin C and tenascin XB, genes possibly involved in tumorigenesis associated with neurofibromatosis type 1. Clin Cancer Res. 2007, 13: 398-407. 10.1158/1078-0432.CCR-06-0182.View ArticlePubMedGoogle Scholar
- Terzi A, Saglam EA, Barak A, Soylemezoglu F: The significance of immunohistochemical expression of Ki-67, p53, p21, and p16 in meningiomas tissue arrays. Pathol Res Pract. 2008, 204: 305-314. 10.1016/j.prp.2008.01.013.View ArticlePubMedGoogle Scholar
- Cancer Genome Anatomy Project. http://cgap.nci.nih.gov/cgci.html.
- Edgar R, Domrachev M, Lash AE: Gene Expression Omnibus: NCBI gene expression and hybridization array data repository. Nucleic Acids Res. 2002, 30: 207-210. 10.1093/nar/30.1.207.View ArticlePubMedPubMed CentralGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1741-7015/11/109/prepub