Medicine (Austin & Northern Health) - Research Publications

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    A genome-wide association study of corneal astigmatism: The CREAM Consortium
    Shah, RL ; Li, Q ; Zhao, W ; Tedja, MS ; Tideman, JWL ; Khawaja, AP ; Fan, Q ; Yazar, S ; Williams, KM ; Verhoeven, VJM ; Xie, J ; Wang, YX ; Hess, M ; Nickels, S ; Lackner, KJ ; Parssinen, O ; Wedenoja, J ; Biino, G ; Concas, MP ; Uitterlinden, A ; Rivadeneira, F ; Jaddoe, VWV ; Hysi, PG ; Sim, X ; Tan, N ; Tham, Y-C ; Sensaki, S ; Hofman, A ; Vingerling, JR ; Jonas, JB ; Mitchell, P ; Hammond, CJ ; Hoehn, R ; Baird, PN ; Wong, T-Y ; Cheng, C-Y ; Teo, YY ; Mackey, DA ; Williams, C ; Saw, S-M ; Klaver, CCW ; Guggenheim, JA ; Bailey-Wilson, JE (MOLECULAR VISION, 2018-02-05)
    PURPOSE: To identify genes and genetic markers associated with corneal astigmatism. METHODS: A meta-analysis of genome-wide association studies (GWASs) of corneal astigmatism undertaken for 14 European ancestry (n=22,250) and 8 Asian ancestry (n=9,120) cohorts was performed by the Consortium for Refractive Error and Myopia. Cases were defined as having >0.75 diopters of corneal astigmatism. Subsequent gene-based and gene-set analyses of the meta-analyzed results of European ancestry cohorts were performed using VEGAS2 and MAGMA software. Additionally, estimates of single nucleotide polymorphism (SNP)-based heritability for corneal and refractive astigmatism and the spherical equivalent were calculated for Europeans using LD score regression. RESULTS: The meta-analysis of all cohorts identified a genome-wide significant locus near the platelet-derived growth factor receptor alpha (PDGFRA) gene: top SNP: rs7673984, odds ratio=1.12 (95% CI:1.08-1.16), p=5.55×10-9. No other genome-wide significant loci were identified in the combined analysis or European/Asian ancestry-specific analyses. Gene-based analysis identified three novel candidate genes for corneal astigmatism in Europeans-claudin-7 (CLDN7), acid phosphatase 2, lysosomal (ACP2), and TNF alpha-induced protein 8 like 3 (TNFAIP8L3). CONCLUSIONS: In addition to replicating a previously identified genome-wide significant locus for corneal astigmatism near the PDGFRA gene, gene-based analysis identified three novel candidate genes, CLDN7, ACP2, and TNFAIP8L3, that warrant further investigation to understand their role in the pathogenesis of corneal astigmatism. The much lower number of genetic variants and genes demonstrating an association with corneal astigmatism compared to published spherical equivalent GWAS analyses suggest a greater influence of rare genetic variants, non-additive genetic effects, or environmental factors in the development of astigmatism.
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    De novo activating epidermal growth factor mutations (EGFR) in small-cell lung cancer
    Thai, A ; Chia, PL ; Russell, PA ; Do, H ; Dobrovic, A ; Mitchell, P ; John, T (WILEY, 2017-09)
    In Australia, mutations in epidermal growth factor mutations (EGFR) occur in 15% of patients diagnosed with non-small-cell lung cancer and are found with higher frequency in female, non-smokers of Asian ethnicity. Activating mutations in the EGFR gene are rarely described in SCLC. We present two cases of de novo EGFR mutations in patients with SCLC detected in tissue and in plasma cell free DNA, both of whom were of Asian ethnicity and never-smokers. These two cases add to the growing body of evidence suggesting that screening for EGFR mutations in SCLC should be considered in patients with specific clinical features.
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    Treatment of ALK-rearranged non- small cell lung cancer: A review of the landscape and approach to emerging patterns of treatment resistance in the Australian context
    Itchins, M ; Chia, PL ; Hayes, SA ; Howell, VM ; Gill, AJ ; Cooper, WA ; John, T ; Mitchell, P ; Millward, M ; Clarke, SJ ; Solomon, B ; Pavlakis, N (WILEY, 2017-08)
    Since the identification of anaplastic lymphoma kinase (ALK) gene rearrangements in non-small cell lung cancer (NSCLC) in 2005, the treatment of ALK-rearranged NSCLC (ALK+ NSCLC) has evolved at a rapid pace. This molecularly distinct subset of NSCLC has uniquely important biology, clinicopathologic features and mechanisms of drug resistance which impact on the choice of treatment for a patient with this disease. There are multiple ALK tyrosine kinase inhibitors now available in clinical practice with efficacy data continuing to emerge and guide the optimal treatment algorithm. A detailed search of medical databases and clinical trial registries was conducted to capture all relevant articles on this topic enabling an updated detailed overview of the landscape of management of ALK-rearranged NSCLC.
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    RET-rearranged non-small-cell lung cancer and therapeutic implications
    Loh, Z ; Mitchell, P ; John, T ; Arulananda, S (WILEY, 2019-12)
    First-line tyrosine kinase inhibitors are standard of care for non-small-cell lung cancers (NSCLC) harbouring an epidermal growth factor receptor mutation, anaplastic lymphoma kinase fusion or c-ros oncogene 1 rearrangement. Other targetable oncogenic drivers have been identified but testing for these is neither funded nor commonly performed in Australia. Using a case example, we discuss the importance of considering several other genomic aberrations in our population, such as rearrangements in the RET proto-oncogene, which occur in 1-2% of lung adenocarcinoma. New oncogenic drivers and corresponding targeted agents are constantly being discovered; these will continue to refine the treatment of non-small-cell lung cancer in the era of precision medicine.
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    The LEAD study protocol: a mixed-method cohort study evaluating the lung cancer diagnostic and pre-treatment pathways of patients from Culturally and Linguistically Diverse (CALD) backgrounds compared to patients from Anglo-Australian backgrounds
    Mazza, D ; Lin, X ; Walter, FM ; Young, JM ; Barnes, DJ ; Mitchell, P ; Brijnath, B ; Martin, A ; Emery, JD (BMC, 2018-07-21)
    BACKGROUND: Lung cancer is the leading cause of cancer mortality worldwide. Early diagnosis and treatment is a key factor in reducing mortality and improving patient outcomes. To achieve this, it is important to understand the diagnostic pathways of cancer patients. Patients from Culturally and Linguistically Diverse (CALD) are a vulnerable group for lung cancer with higher mortality rates than Caucasian patients. The aim of this study is to explore differences in the lung cancer diagnostic pathways between CALD and Anglo-Australian patients and factors underlying these differences. METHODS: This is a prospective, observational cohort study using a mixed-method approach. Quantitative data regarding time intervals in the lung cancer diagnostic pathways will be gathered via patient surveys, General practitioner (GP) review of general practice records, and case-note analysis of hospital records. Qualitative data will be gathered via structured interviews with lung cancer patients, GPs, and hospital specialists. The study will be conducted in five study sites across three states in Australia. Anglo-Australian patients and patients from five CALD groups (i.e., Arabic, Chinese, Greek, Italian and Vietnamese communities) will mainly be identified through the list of new cases presented at lung multidisciplinary team meetings. For the quantitative component, it is anticipated that 724 patients (362 Anglo-Australian and 362 CALD patients) will be recruited to obtain a final sample of 290 (145 per group) assuming a 50% patient survey completion rate and a 80% GP record review completion rate. For the qualitative component, 60 interviews with lung cancer patients (10 Anglo-Australian and 10 patients per CALD group), 20 interviews with GPs, and 20 interviews with specialists will be conducted. DISCUSSION: This is the first Australian study to compare the time intervals along the lung cancer diagnostic pathway between CALD and Anglo-Australian patients. The study will also explore the underlying patient, healthcare provider, and health system factors that influence the time intervals in the two groups. This information will improve our understanding of the effect of ethnicity on health outcomes among lung cancer patients and will inform future interventions aimed at early diagnosis and treatment for lung cancer, particularly patients from CALD backgrounds. TRIAL REGISTRATION: The project was retrospectively registered with Australian New Zealand Clinical Trials Registry (registration number: ACTRN12617000957392 , date registered: 4th July 2017).
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    A phase 2, single-arm study of an autologous dendritic cell treatment against mucin 1 in patients with advanced epithelial ovarian cancer
    Mitchell, PLR ; Quinn, MA ; Grant, PT ; Allen, DG ; Jobling, TW ; White, SC ; Zhao, A ; Karanikas, V ; Vaughan, H ; Pietersz, G ; McKenzie, IFC ; Gargosky, SE ; Loveland, BE (BMC, 2014)
    BACKGROUND: Mucin 1 antigen, highly expressed by epithelial ovarian cancer (EOC), is a potential target for immunotherapy. A previous successful phase 1 trial was conducted in patients with adenocarcinoma who were injected with Cvac, autologous monocyte-derived dendritic cells (DCs) incubated with mannosylated mucin 1 protein (M-FP). The present study was a phase 2 trial of Cvac in patients with advanced EOC. METHODS: Eligible patients had EOC with progressive disease, defined as an increase in CA125 of ≥ 25% in 1 month. The primary endpoint was CA125 response or stabilization. Peripheral blood mononuclear cells were collected by leukapheresis and cultured to generate DCs. The DC were incubated with M-FP, and after washing were prepared for injection into the patient intradermally every 4 weeks for 3 doses, then every 10 weeks for up to 12 months. RESULTS: All 28 patients recruited were evaluable for safety and 26 for efficacy. All had undergone surgery and platinum-based chemotherapy, and 57% of patients received ≥ 3 chemotherapy regimens. There were no Grade 3 or 4 toxicities considered related to Cvac. Four patients showed CA125 response or stabilization (2 patients with major responses, 1 minor response, 1 stabilization) of median duration 10.3 months (5.3-16.3 months). An additional patient had > 25% CA125 reduction (not confirmed). CONCLUSIONS: Cvac immunotherapy was well tolerated. Clinical activity in EOC was evident based on decline or stabilization of CA125 in some patients, supporting ongoing development of Cvac in ovarian carcinoma and planning of additional trials of patients in remission is currently underway.
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    A critical re-assessment of DNA repair gene promoter methylation in non-small cell lung carcinoma
    Do, H ; Wong, NC ; Murone, C ; John, T ; Solomon, B ; Mitchell, PL ; Dobrovic, A (NATURE PORTFOLIO, 2014-02-26)
    DNA repair genes that have been inactivated by promoter methylation offer potential therapeutic targets either by targeting the specific repair deficiency, or by synthetic lethal approaches. This study evaluated promoter methylation status for eight selected DNA repair genes (ATM, BRCA1, ERCC1, MGMT, MLH1, NEIL1, RAD23B and XPC) in 56 non-small cell lung cancer (NSCLC) tumours and 11 lung cell lines using the methylation-sensitive high resolution melting (MS-HRM) methodology. Frequent methylation in NEIL1 (42%) and infrequent methylation in ERCC1 (2%) and RAD23B (2%) are reported for the first time in NSCLC. MGMT methylation was detected in 13% of the NSCLCs. Contrary to previous studies, methylation was not detected in ATM, BRCA1, MLH1 and XPC. Data from The Cancer Genome Atlas (TCGA) was consistent with these findings. The study emphasises the importance of using appropriate methodology for accurate assessment of promoter methylation.
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    Pharmacodynamic analysis of tumour perfusion assessed by 15O-water-PET imaging during treatment with sunitinib malate in patients with advanced malignancies
    Scott, AM ; Mitchell, PL ; O'Keefe, G ; Saunder, T ; Hicks, RJ ; Poon, A ; Baum, C ; Brega, N ; McCarthy, TJ ; Toner, GC (SPRINGEROPEN, 2012)
    BACKGROUND: We evaluated pharmacodynamic changes in tumour perfusion using positron emission tomography (PET) imaging with 15O-water to assess biological response to sunitinib, a multitargeted tyrosine kinase inhibitor. METHODS: Patients with advanced malignancies received sunitinib 50 mg/day orally, once daily for 4 weeks on treatment, followed by 2 weeks off treatment, in repeated 6-week cycles. Quantitative measurement of tumour perfusion was assessed using 15O-water-PET at baseline and after 2 weeks of treatment. At least one reference tumour lesion was included in the fields of view and assessed at both time points. Patients also underwent 18 F-fluorodeoxyglucose (FDG)-PET imaging at baseline and after 2 and 4 weeks of treatment. Radiological response of the reference tumour lesion and overall radiological response were assessed at week 12. Serum pharmacokinetic and biomarker analyses were also performed. RESULTS: Data were available for seven patients. Compared with baseline, all patients experienced a decrease in reference tumour blood flow ranging from 20 % to 85 % and also a reduction in the FDG standard uptake value ranging from 29 % to 67 %. Six patients experienced a partial metabolic response based on FDG-PET criteria. Four patients had stable disease defined by radiological response (Response Evaluation Criteria in Solid Tumors) lasting between 4 and 12 cycles. An association between perfusion change and clinical benefit, and biomarker levels including vascular endothelial growth factor was observed. CONCLUSION: Administering sunitinib to patients with advanced malignancies is associated with early biological responses, including decreased blood flow in secondary tumour deposits.
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    PD-L1 and Tumor Infiltrating Lymphocytes as Prognostic Markers in Resected NSCLC
    Ameratunga, M ; Asadi, K ; Lin, X ; Walkiewicz, M ; Murone, C ; Knight, S ; Mitchell, P ; Boutros, P ; John, T ; de Mello, RA (PUBLIC LIBRARY SCIENCE, 2016-04-22)
    INTRODUCTION: Immune checkpoint inhibition has shifted treatment paradigms in non-small cell lung cancer (NSCLC). Conflicting results have been reported regarding the immune infiltrate and programmed death-ligand 1 (PD-L1) as a prognostic marker. We correlated the immune infiltrate and PD-L1 expression with clinicopathologic characteristics in a cohort of resected NSCLC. METHODS: A tissue microarray was constructed using triplicate cores from consecutive resected NSCLC. Immunohistochemistry was performed for CD8, FOXP3 and PD-L1. Strong PD-L1 expression was predefined as greater than 50% tumor cell positivity. Matched nodal samples were assessed for concordance of PD-L1 expression. RESULTS: Of 522 patients, 346 were node-negative (N0), 72 N1 and 109 N2; 265 were adenocarcinomas (AC), 182 squamous cell cancers (SCC) and 75 other. Strong PD-L1 expression was found in 24% cases. In the overall cohort, PD-L1 expression was not associated with survival. In patients with N2 disease, strong PD-L1 expression was associated with significantly improved disease-free (DFS) and overall survival (OS) in multivariate analysis (HR 0.49, 95%CI 0.36-0.94, p = 0.031; HR 0.46, 95%CI 0.26-0.80, p = 0.006). In this resected cohort only 5% harboured EGFR mutations, whereas 19% harboured KRAS and 23% other. KRAS mutated tumors were more likely to highly express PD-L1 compared to EGFR (22% vs 3%). A stromal CD8 infiltrate was associated with significantly improved DFS in SCC (HR 0.70, 95%CI 0.50-0.97, p = 0.034), but not AC, whereas FOXP3 was not prognostic. Matched nodal specimens (N = 53) were highly concordant for PD-L1 expression (89%). CONCLUSION: PD-L1 expression was not prognostic in the overall cohort. PD-L1 expression in primary tumor and matched nodal specimens were highly concordant. The observed survival benefit in N2 disease requires confirmation.