Sir Peter MacCallum Department of Oncology - Research Publications
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ItemNo Preview AvailablePheo-Type: A Diagnostic Gene-expression Assay for the Classification of Pheochromocytoma and Paraganglioma(ENDOCRINE SOC, 2016-03-01)CONTEXT: Pheochromocytomas and paragangliomas (PPGLs) are heritable neoplasms that can be classified into gene-expression subtypes corresponding to their underlying specific genetic drivers. OBJECTIVE: This study aimed to develop a diagnostic and research tool (Pheo-type) capable of classifying PPGL tumors into gene-expression subtypes that could be used to guide and interpret genetic testing, determine surveillance programs, and aid in elucidation of PPGL biology. DESIGN: A compendium of published microarray data representing 205 PPGL tumors was used for the selection of subtype-specific genes that were then translated to the Nanostring gene-expression platform. A support vector machine was trained on the microarray dataset and then tested on an independent Nanostring dataset representing 38 familial and sporadic cases of PPGL of known genotype (RET, NF1, TMEM127, MAX, HRAS, VHL, and SDHx). Different classifier models involving between three and six subtypes were compared for their discrimination potential. RESULTS: A gene set of 46 genes and six endogenous controls was selected representing six known PPGL subtypes; RTK1-3 (RET, NF1, TMEM127, and HRAS), MAX-like, VHL, and SDHx. Of 38 test cases, 34 (90%) were correctly predicted to six subtypes based on the known genotype to gene-expression subtype association. Removal of the RTK2 subtype from training, characterized by an admixture of tumor and normal adrenal cortex, improved the classification accuracy (35/38). Consolidation of RTK and pseudohypoxic PPGL subtypes to four- and then three-class architectures improved the classification accuracy for clinical application. CONCLUSIONS: The Pheo-type gene-expression assay is a reliable method for predicting PPGL genotype using routine diagnostic tumor samples.
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ItemNo Preview AvailableTERT structural rearrangements in metastatic pheochromocytomas(BIOSCIENTIFICA LTD, 2018-01-01)Pheochromocytomas (PC) and paragangliomas (PGL) are endocrine tumors for which the genetic and clinicopathological features of metastatic progression remain incompletely understood. As a result, the risk of metastasis from a primary tumor cannot be predicted. Early diagnosis of individuals at high risk of developing metastases is clinically important and the identification of new biomarkers that are predictive of metastatic potential is of high value. Activation of TERT has been associated with a number of malignant tumors, including PC/PGL. However, the mechanism of TERT activation in the majority of PC/PGL remains unclear. As TERT promoter mutations occur rarely in PC/PGL, we hypothesized that other mechanisms - such as structural variations - may underlie TERT activation in these tumors. From 35 PC and four PGL, we identified three primary PCs that developed metastases with elevated TERT expression, each of which lacked TERT promoter mutations and promoter DNA methylation. Using whole genome sequencing, we identified somatic structural alterations proximal to the TERT locus in two of these tumors. In both tumors, the genomic rearrangements led to the positioning of super-enhancers proximal to the TERT promoter, that are likely responsible for the activation of the normally tightly repressed TERT expression in chromaffin cells.
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ItemAutomated preparation of 2-[F-18]fluoropropionate labeled peptides using a flexible, multi-stage synthesis platform (iPHASE Flexlab)(WILEY, 2018-02-01)Radiolabelled peptides are vital tools used in positron emission tomography imaging for the diagnosis of disease, drug discovery, and biomedical research. Peptides are typically labeled through conjugation to a radiolabelled prosthetic group, which usually necessitates complex, multi-step procedures, especially for fluorine-18 labeled peptides. Herein, we describe the automated synthesis and formulation of 2-[18 F]fluoropropionate labeled RGD-peptides through use of the iPHASE Flexlab as an effective dual-stage radiochemical synthesis module. The fully automated preparation of the monomeric RGD-peptides, [18 F]FP-GalactoRGD and [18 F]FP-c(RGDy(SO3 )K), was accomplished in under 90 minutes with n.d.c. radiochemical yields ca. 7% from fluoride. Similarly, the automated preparation of the dimeric RGD-peptides, [18 F]F-PRGD2 and [18 F]FP-E(RGDy(SO3 )K)2 , was accomplished in under 105 minutes with n.d.c. yields ca. 4% from fluoride.
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ItemAcute radiation oesophagitis associated with 2-deoxy-2-[18F]fluoro-d-glucose uptake on positron emission tomography/CT during chemo-radiation therapy in patients with non-small-cell lung cancer(WILEY, 2017-10-01)INTRODUCTION: Acute radiation oesophagitis (ARO) is frequently experienced by patients receiving concurrent chemo-radiation therapy (cCRT) for non-small-cell lung cancer (NSCLC). We investigated ARO symptoms (CTCAE v3.0), radiation dose and oesophageal FDG PET/CT uptake. METHOD: Candidates received cCRT (60 Gy, 2 Gy/fx) and sequential FDG PET/CT (baseline FDG0 , FDGwk2 and FDGwk4 ). Mean and maximum standardized uptake value (SUVmean and SUVmax) and radiation dose (Omean and Omax ) were calculated within the whole oesophagus and seven sub-regions (5-60 Gy). RESULTS: Forty-four patients underwent FDG0 and FDGwk2 , and 41 (93%) received FDGwk4 , resulting in 129 PET/CT scans for analysis. Of 29 (66%) patients with ≥ grade 2 ARO, SUVmax (mean ± SD) increased from FDG0 to FDGwk4 (3.06 ± 0.69 to 3.83 ± 1.27, P = 0.0019) and FDGwk2 to FDGwk4 (3.10 ± 0.75 to 3.83 ± 1.27, P = 0.0046). Radiation dose (mean ± SD) was higher in grade ≥2 patients; Omean (47.5 ± 20 vs 53.9 ± 10.2, P = 0.0061), Omax (13.7 ± 9.6 vs 20.1 ± 10.6, P = 0.0009) and V40 Gy (8.0 ± 8.2 vs 11.9 ± 7.3, P = 0.0185). CONCLUSIONS: FDGwk4 SUVmax and radiation dose were associated with ≥ grade 2 ARO. Compared to subjective assessments, future interim FDG PET/CT acquired for disease response assessment may also be utilized to objectively characterize ARO severity and image-guided oesophageal dose constraints.
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ItemIntense focal pituitary FDG uptake due to intravascular large B-cell lymphoma in pyrexia of unknown origin(WILEY-BLACKWELL, 2016-11-01)
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ItemLong term, continuous exposure to panobinostat induces terminal differentiation and long term survival in the TH-MYCN neuroblastoma mouse model(WILEY, 2016-07-01)Neuroblastoma is the most common extra-cranial malignancy in childhood and accounts for ∼15% of childhood cancer deaths. Amplification of MYCN in neuroblastoma is associated with aggressive disease and predicts for poor prognosis. Novel therapeutic approaches are therefore essential to improving patient outcomes in this setting. The histone deacetylases are known to interact with N-Myc and regulate numerous cellular processes via epigenetic modulation, including differentiation. In this study, we used the TH-MYCN mouse model of neuroblastoma to investigate the antitumor activity of the pan-HDAC inhibitor, panobinostat. In particular we sought to explore the impact of long term, continuous panobinostat exposure on the epigenetically driven differentiation process. Continuous treatment of tumor bearing TH-MYCN transgenic mice with panobinostat for nine weeks led to a significant improvement in survival as compared with mice treated with panobinostat for a three-week period. Panobinostat induced rapid tumor regression with no regrowth observed following a nine-week treatment period. Initial tumor response was associated with apoptosis mediated via upregulation of BMF and BIM. The process of terminal differentiation of neuroblastoma into benign ganglioneuroma, with a characteristic increase in S100 expression and reduction of N-Myc expression, occurred following prolonged exposure to the drug. RNA-sequencing analysis of tumors from treated animals confirmed significant upregulation of gene pathways associated with apoptosis and differentiation. Together our data demonstrate the potential of panobinostat as a novel therapeutic strategy for high-risk neuroblastoma patients.
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ItemA Bivalent Inhibitor of Prostate Specific Membrane Antigen Radiolabeled with Copper-64 with High Tumor Uptake and Retention(WILEY-V C H VERLAG GMBH, 2019-09-05)Molecules containing lysine-ureido-glutamate functional groups bind to the active site of prostate specific membrane antigen, which is overexpressed in prostate cancer. To prepare copper radiopharmaceuticals for the diagnosis and therapy of prostate cancer, macrobicyclic sarcophagine ligands tethered to either one or two lysine-ureido-glutamate functional groups through an appropriate linker have been prepared. Sarcophagine ligands can be readily radiolabeled with positron-emitting copper-64 at room temperature. The bivalent agent, in which two targeting groups are tethered to a single copper complex, dramatically outperforms the monomeric agent with respect to tumor uptake and retention. The high tumor uptake, low background, and prolonged tumor retention, even at 24 hours post injection, suggest the bivalent agent is a promising diagnostic for prostate cancer and could be used for prospective dosimetry for therapy with a copper-67 variant.
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