Sally R Lambert

University of Cambridge, Cambridge, England, United Kingdom

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Publications (17)125.67 Total impact

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    ABSTRACT: Background:Cutaneous squamous cell carcinoma (cSCC) is one of the most common malignancies in fair-skinned populations worldwide and its incidence is increasing. Despite previous observations of multiple genetic abnormalities in cSCC, the oncogenic process remains elusive. The purpose of this study was to elucidate key molecular events associated with progression from premalignant actinic keratoses (AKs) to invasive cSCC by transcriptome profiling.Methods:We combined laser capture microdissection with the Affymetrix HGU133 Plus 2.0 microarrays to profile 30 cSCC and 10 AKs.Results:We identified a core set of 196 genes that are differentially expressed between AK and cSCC, and are enriched for processes including epidermal differentiation, cell migration, cell-cycle regulation and metabolism. Gene set enrichment analysis highlighted a key role for the mitogen activated protein kinase (MAPK) pathway in cSCC compared with AK. Furthermore, the histological subtype of the tumour was shown to influence the expression profile.Conclusion:These data indicate that the MAPK pathway may be pivotal to the transition from AK to cSCC, thus representing a potential target for cSCC prevention. In addition, transcriptome differences identified between cSCC subtypes have important implications for future development of targeted therapies for this malignancy.British Journal of Cancer advance online publication, 12 December 2013; doi:10.1038/bjc.2013.760 www.bjcancer.com.
    British Journal of Cancer 12/2013; 110(2). DOI:10.1038/bjc.2013.760 · 4.82 Impact Factor
  • Cancer Research 08/2013; 73(8 Supplement):3807-3807. DOI:10.1158/1538-7445.AM2013-3807 · 9.28 Impact Factor
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    ABSTRACT: Pilocytic astrocytoma, the most common childhood brain tumor, is typically associated with mitogen-activated protein kinase (MAPK) pathway alterations. Surgically inaccessible midline tumors are therapeutically challenging, showing sustained tendency for progression and often becoming a chronic disease with substantial morbidities. Here we describe whole-genome sequencing of 96 pilocytic astrocytomas, with matched RNA sequencing (n = 73), conducted by the International Cancer Genome Consortium (ICGC) PedBrain Tumor Project. We identified recurrent activating mutations in FGFR1 and PTPN11 and new NTRK2 fusion genes in non-cerebellar tumors. New BRAF-activating changes were also observed. MAPK pathway alterations affected all tumors analyzed, with no other significant mutations identified, indicating that pilocytic astrocytoma is predominantly a single-pathway disease. Notably, we identified the same FGFR1 mutations in a subset of H3F3A-mutated pediatric glioblastoma with additional alterations in the NF1 gene. Our findings thus identify new potential therapeutic targets in distinct subsets of pilocytic astrocytoma and childhood glioblastoma.
    Nature Genetics 06/2013; Epub ahead of print. DOI:10.1038/ng.2682. · 29.65 Impact Factor
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    ABSTRACT: Pilocytic astrocytomas occur predominantly in childhood. In contrast to the posterior fossa location, hypothalamo-chiasmatic pilocytic astrocytomas display a worse prognosis often leading to multiple surgical procedures and/or several lines of chemotherapy and radiotherapy to achieve long-term control. Hypothalamo-chiasmatic pilocytic astrocytomas and cerebellar pilocytic astrocytomas have a distinctive gene signature and several differential expressed genes (ICAM1, CRK, CD36, and IQGAP1) are targets for available drugs: fluvastatin and/or celecoxib. Quantification by RT-Q-PCR of the expression of these genes was performed in a series of 51 pilocytic astrocytomas and 10 glioblastomas: they were all significantly overexpressed in hypothalamo-chiasmatic pilocytic astrocytomas relative to cerebellar pilocytic astrocytomas, and CRK and ICAM1 were significantly overexpressed in pilocytic astrocytomas versus glioblastomas.We used two commercially available glioblastoma cell lines and three pilocytic astrocytoma explant cultures to investigate the effect of celecoxib/fluvastatin alone or in combination. Glioblastoma cell lines were sensitive to both drugs and a combination of 100 μM celecoxib and 240 μM fluvastatin was the most synergistic. This synergistic combination was used on the explant cultures and led to massive cell death of pilocytic astrocytoma cells.As a proof of concept, a patient with a refractory multifocal pilocytic astrocytoma was successfully treated with the fluvastatin/celecoxib combination used for 18 months. It was well tolerated and led to a partial tumor response. This study reports evidence for new targets and synergistic effect of celecoxib/fluvastatin combination in pilocytic astrocytoma. Because it is non-toxic, this new strategy offers hope for the treatment of patients with refractory pilocytic astrocytoma.
    05/2013; 1(1):17. DOI:10.1186/2051-5960-1-17
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    ABSTRACT: Pilocytic astrocytomas (PAs) are the most common brain tumors in pediatric patients and can cause significant morbidity, including chronic neurological deficiencies. They are characterized by activating alterations in the mitogen-activated protein kinase pathway, but little else is known about their development. To map the global DNA methylation profiles of these tumors, we analyzed 62 PAs and 7 normal cerebellum samples using Illumina 450K microarrays. These data revealed two subgroups of PA that separate according to tumor location (infratentorial versus supratentorial), and identified key neural developmental genes that are differentially methylated between the two groups, including NR2E1 and EN2. Integration with transcriptome microarray data highlighted significant expression differences, which were unexpectedly associated with a strong positive correlation between methylation and expression. Differentially methylated probes were often identified within the gene body and/or regions up- or downstream of the gene, rather than at the transcription start site. We also identified a large number of differentially methylated genes between cerebellar PAs and normal cerebellum, which were again enriched for developmental genes. In addition, we found a significant association between differentially methylated genes and SUZ12 binding sites, indicating potential disruption of the polycomb repressor complex 2 (PRC2). Taken together, these data suggest that PA from different locations in the brain may arise from region-specific cells of origin, and highlight the potential disruption of key developmental regulators during tumorigenesis. These findings have implications for future basic research and clinical trials, as therapeutic targets and drug sensitivity may differ according to tumor location.
    Acta Neuropathologica 05/2013; DOI:10.1007/s00401-013-1124-7 · 9.78 Impact Factor
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    ABSTRACT: Cutaneous squamous cell carcinoma (cSCC) is the second most common form of nonmelanoma skin cancer (NMSC), and its incidence is increasing rapidly. Metastatic cSCC accounts for the majority of deaths associated with NMSC, but the genetic basis for cSCC progression remains poorly understood. A previous study identified small deletions (typically <1 Mb) in the protein tyrosine phosphatase receptor Type D (PTPRD) gene that segregated with more aggressive cSCC. To investigate the apparent association between deletion within PTPRD and cSCC metastasis, a series of 74 formalin-fixed paraffin-embedded tumors from 31 patients was analyzed using a custom Illumina 384 SNP microarray. Deletions were found in 37% of patients with metastatic cSCC and were strongly associated with metastatic tumors when compared to those that had not metastasized (p = 0.007). Subsequent mutation analysis revealed a higher mutation rate for PTPRD than has been reported in any other cancer type, with 37% of tumors harboring a somatic mutation. Conversely, bisulfite sequencing showed that methylation was not a mechanism of PTPRD disruption in cSCC. This is the first report to observe an association between deletion within PTPRD and metastatic disease and highlights the potential use of these deletions as a diagnostic biomarker for tumor progression. Combined with the high mutation rate observed in our study, PTPRD is one of the most commonly altered genes in cSCC and warrants further investigation to determine its significance for metastasis in other tumor types.
    International Journal of Cancer 08/2012; 131(3):E216-26. DOI:10.1002/ijc.27333 · 5.01 Impact Factor
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    ABSTRACT: Rosette-forming glioneuronal tumors (RGNT) of the fourth ventricle are rare mixed glioneuronal tumors included in the revised WHO classification of central nervous system tumors, showing partial histological similarities to pilocytic astrocytomas. To evaluate potential similarities at the molecular level between these tumors, we analysed a series of 10 RGNT for the presence of KIAA1549-BRAF fusions using interphase fluorescence in situ hybridisation. However, we found no cases showing KIAA1549-BRAF gene fusion or BRAF (V600E) mutation. Our data support the hypothesis that RGNT may represent a distinct entity among the glioneuronal tumors of the central nervous system, with molecular features different from pilocytic astrocytomas.
    Journal of Neuro-Oncology 07/2012; 110(1):21-5. DOI:10.1007/s11060-012-0940-2 · 2.79 Impact Factor
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    ABSTRACT: Cerebellar low-grade astrocytomas with a diffuse pattern of growth are uncommon, comprising World Health Organization (WHO) grade II diffuse astrocytomas (DA) and a minority of WHO grade I pilocytic astrocytomas (PA), so-called PA, "diffuse variant." Among 106 cerebellar low-grade astrocytomas (WHO grade I and II) operated on at the Mayo Clinic (1984-2010), we identified 19 such cases: 8 PA, "diffuse variant," 5 DA, and 6 that we were unable to classify further (low-grade astrocytomas, subtype indeterminate). We characterized these tumors using immunohistochemistry and currently available molecular markers (IDH1/2 mutations and BRAF mutation/fusion gene status) and investigated whether the markers could be used to aid the diagnostic process in combination with the clinical and pathologic features. KIAA1549-BRAF fusion was detected in 4 PA, "diffuse variant," 2 DA, and 2 low-grade astrocytomas, subtype indeterminate, indicating that these tumors were molecularly consistent with PA, the most common subtype of the series. A BRAF V600E mutation was detected in 1 PA, "diffuse variant" case; an IDH1 R132G mutation was found in 1 DA case. These results suggest that KIAA1549-BRAF fusion status and IDH1/2 and BRAF V600E mutational analyses may assist in the histologic classification of this diagnostically challenging group of tumors and result in a more accurate and objective combined molecular and histologic classification.
    Journal of Neuropathology and Experimental Neurology 06/2012; 71(7):631-9. DOI:10.1097/NEN.0b013e31825c448a · 4.37 Impact Factor
  • American Journal of Clinical Dermatology 02/2012; 13(1):64-5. DOI:10.2165/11593910-000000000-00000 · 2.52 Impact Factor
  • Klinische Pädiatrie 11/2011; 223(06). DOI:10.1055/s-0031-1292584 · 1.90 Impact Factor
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    ABSTRACT: The CD95/CD95L receptor-ligand system is mainly recognised in the induction of apoptosis. However, it has also been shown that CD95L is over-expressed in many cancer types where it modulates immune-evasion and together with its receptor CD95 promotes tumour growth. Here, we show that CD95 surface modification of relatively large microparticles >0.5 μm in diameter, including those made from biodegradable polylactic-co-glycolic acid (PLGA), enhances intracellular uptake by a range of CD95L expressing cells in a process akin to phagocytosis. Using this approach we describe the intracellular uptake of microparticles and agent delivery in neurons, medulloblastoma, breast and ovarian cancer cells in vitro. CD95 modified paclitaxel-loaded PLGA microparticles are shown to be significantly more effective compared to conventional paclitaxel therapy (Taxol) at the same dose in subcutaneous medulloblastoma (∗∗∗P < 0.0001) and orthotopic ovarian cancer xenograft models where a >65-fold reduction in tumour bioluminescence was measured after treatment (∗P = 0.012). This drug delivery platform represents a new way of manipulating the normally advantageous tumour CD95L over-expression towards a therapeutic strategy. CD95 functionalised drug carriers could contribute to the improved function of cytotoxics in cancer, potentially increasing drug targeting and efficacy whilst reducing toxicity.
    Biomaterials 08/2011; 32(33):8538-47. DOI:10.1016/j.biomaterials.2011.07.060 · 8.31 Impact Factor
  • Cancer Research 07/2011; 71(8 Supplement):4699-4699. DOI:10.1158/1538-7445.AM2011-4699 · 9.28 Impact Factor
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    ABSTRACT: Oncogenic BRAF/Ras or NF1 loss can potentially trigger oncogene-induced senescence (OIS) through activation of the mitogen-activated protein kinase (MAPK) pathway. Somatic genetic abnormalities affecting this pathway occur in the majority of pilocytic astrocytomas (PA), the most prevalent brain neoplasm in children. We investigated whether OIS is induced in PA. We tested expression of established senescence markers in three independent cohorts of sporadic PA. We also assessed for OIS in vitro, using forced expression of wild-type and V600E-mutant BRAF in two astrocytic cell lines: human telomerase reverse transcriptase (hTERT)-immortalized astrocytes and fetal astrocytes. Our results indicate that PAs are senescent as evidenced by marked senescence-associated acidic β-galactosidase activity, low KI-67 index, and induction of p16(INK4a) but not p53 in the majority of 52 PA samples (46 of 52; 88.5%). Overexpression of a number of senescence-associated genes [CDKN2A (p16), CDKN1A (p21), CEBPB, GADD45A, and IGFBP7] was shown at the mRNA level in two independent PA tumor series. In vitro, sustained activation of wild-type or mutant BRAF induced OIS in both astrocytic cell lines. Loss of p16(INK4a) in immortalized astrocytes abrogated OIS, indicative of the role of this pathway in mediating this phenomenon in astrocytes. OIS is a mechanism of tumor suppression that restricts the progression of benign tumors. We show that it is triggered in PAs through p16(INK4a) pathway induction following aberrant MAPK activation. OIS may account for the slow growth pattern in PA, the lack of progression to higher-grade astrocytomas, and the high overall survival of affected patients.
    Clinical Cancer Research 05/2011; 17(14):4650-60. DOI:10.1158/1078-0432.CCR-11-0127 · 8.19 Impact Factor
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    ABSTRACT: Activation of the MAPK signaling pathway has been shown to be a unifying molecular feature in pilocytic astrocytoma (PA). Genetically, tandem duplications at chromosome 7q34 resulting in KIAA1549-BRAF fusion genes constitute the most common mechanism identified to date. To elucidate alternative mechanisms of aberrant MAPK activation in PA, we screened 125 primary tumors for RAF fusion genes and mutations in KRAS, NRAS, HRAS, PTPN11, BRAF and RAF1. Using microarray-based comparative genomic hybridization (aCGH), we identified in three cases an interstitial deletion of ~2.5 Mb as a novel recurrent mechanism forming BRAF gene fusions with FAM131B, a currently uncharacterized gene on chromosome 7q34. This deletion removes the BRAF N-terminal inhibitory domains, giving a constitutively active BRAF kinase. Functional characterization of the novel FAM131B-BRAF fusion demonstrated constitutive MEK phosphorylation potential and transforming activity in vitro. In addition, our study confirmed previously reported BRAF and RAF1 fusion variants in 72% (90/125) of PA. Mutations in BRAF (8/125), KRAS (2/125) and NF1 (4/125) and the rare RAF1 gene fusions (2/125) were mutually exclusive with BRAF rearrangements, with the exception of two cases in our series that concomitantly harbored more than one hit in the MAPK pathway. In summary, our findings further underline the fundamental role of RAF kinase fusion products as a tumor-specific marker and an ideally suited drug target for PA.
    Acta Neuropathologica 03/2011; 121(6):763-74. DOI:10.1007/s00401-011-0817-z · 9.78 Impact Factor
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    ABSTRACT: Diffuse astrocytomas (WHO grade II) typically present as slow-growing tumours showing significant cellular differentiation, but possessing a tendency towards malignant progression. They account for ~10% of all astrocytic tumours, with a peak incidence between 30 and 40 years of age. Median survival is reported as around 6-8 years. Mutations of TP53 and IDH1 have been described as genetic hallmarks, while copy number alterations are also relatively common. However, there is some evidence to suggest that these characteristics may vary with age. Here, we present an integrated clinicopathologic, genomic and transcriptomic analysis suggesting that paediatric and adult tumours are associated with distinct genetic signatures. For example, no childhood tumour showed mutation of IDH1/2 or TP53, virtually no copy number changes were seen, and MGMT methylation was absent. In contrast, adult tumours showed IDH1/2 mutation in 94% and TP53 mutation in 69% of cases, with multiple copy number alterations per case and hypermethylation of MGMT in the majority of tumours. These differences were associated with a worse prognosis in the adult patients. The expression array data also revealed a significant difference in the expression of a number of genes putatively involved in neural stem cell maintenance and CNS development, including DLL3, HES5, BMP2, TIMP1 and BAMBI. Genes involved in DNA replication and the cell cycle were also enriched in the adult tumours, suggesting that their more aggressive behaviour may be due to derivation from a more rapidly dividing, less differentiated cell type.
    Acta Neuropathologica 02/2011; 121(6):753-61. DOI:10.1007/s00401-011-0810-6 · 9.78 Impact Factor
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    ABSTRACT: Cutaneous squamous cell carcinomas (cSCCs) are the second most frequent cancers in fair-skinned populations; yet, because of their genetic heterogeneity, the key molecular events in cSCC tumorigenesis remain poorly defined. We have used single nucleotide polymorphism microarray analysis to examine genome-wide allelic imbalance in 60 cSCCs using paired non-tumor samples. The most frequent recurrent aberrations were loss of heterozygosity at 3p and 9p, observed in 39 (65%) and 45 (75%) tumors, respectively. Microdeletions at 9p23 within the protein tyrosine phosphatase receptor type D (PTPRD) locus were identified in 9 (15%) samples, supporting a tumor suppressor role for PTPRD in cSCC. In addition, microdeletions at 3p14.2 were detected in 3 (5%) cSCCs, implicating the fragile histidine triad (FHIT) gene as a possible target for inactivation. Statistical analysis revealed that well-differentiated cSCCs demonstrated significantly fewer aberrations than moderately and poorly differentiated cSCCs; yet, despite a lower rate of allelic imbalance, some specific aberrations were observed equally frequently in both groups. No correlation was established between the frequency of chromosomal aberrations and immune or human papillomavirus status. Our data suggest that well-differentiated tumors are a genetically distinct subpopulation of cSCC.
    Journal of Investigative Dermatology 02/2009; 129(6):1562-8. DOI:10.1038/jid.2008.408 · 6.37 Impact Factor
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    ABSTRACT: Cutaneous squamous cell carcinomas (SCC) are the second most commonly diagnosed cancers in fair-skinned people; yet the genetic mechanisms involved in SCC tumorigenesis remain poorly understood. We have used single nucleotide polymorphism (SNP) microarray analysis to examine genome-wide allelic imbalance in 16 primary and 2 lymph node metastatic SCC using paired non-tumour samples to counteract normal copy number variation. The most common genetic change was loss of heterozygosity (LOH) on 9p, observed in 13 of 16 primary SCC. Other recurrent events included LOH on 3p (9 tumors), 2q, 8p, and 13 (each in 8 SCC) and allelic gain on 3q and 8q (each in 6 tumors). Copy number-neutral LOH was observed in a proportion of samples, implying that somatic recombination had led to acquired uniparental disomy, an event not previously demonstrated in SCC. As well as recurrent patterns of gross chromosomal changes, SNP microarray analysis revealed, in 2 primary SCC, a homozygous microdeletion on 9p23 within the protein tyrosine phosphatase receptor type D (PTPRD) locus, an emerging frequent target of homozygous deletion in lung cancer and neuroblastoma. A third sample was heterozygously deleted within this locus and PTPRD expression was aberrant. Two of the 3 primary SCC with PTPRD deletion had demonstrated metastatic potential. Our data identify PTPRD as a candidate tumor suppressor gene in cutaneous SCC with a possible association with metastasis.
    Genes Chromosomes and Cancer 07/2007; 46(7):661-9. DOI:10.1002/gcc.20447 · 3.84 Impact Factor

Publication Stats

215 Citations
125.67 Total Impact Points

Institutions

  • 2011–2013
    • University of Cambridge
      • Department of Pathology
      Cambridge, England, United Kingdom
  • 2009–2013
    • Queen Mary, University of London
      Londinium, England, United Kingdom
  • 2007–2012
    • University of London
      • The London School of Medicine and Dentistry
      Londinium, England, United Kingdom