Differential proteomic alterations between localised and metastatic prostate cancer

Molecular alterations in the prostate cancer proteome mediate the functional and phenotypic transformation from clinically localised to metastatic cancer, a transition that drives patient's mortality and challenges therapeutic intervention. A first approximation of differential proteomic alterations stratified by disease stage has yielded repertoires of potential diagnostic and prognostic markers, multiplex signatures of predictive value, and yield fundamental insight into molecular commonalities in cancer progression. Deciphering these causative proteomic alterations from the molecular noise will continue to mature our understanding of tumour biology and drive new computational and integrative approaches to model a system's view that accommodates the heterogeneity of prostate cancer progression

Characterisation of experimentally induced and spontaneously occurring disease within captive bred dasyurids

Neosporosis is a disease of worldwide distribution resulting from infection by the obligate intracellular apicomplexan protozoan parasite Neospora caninum, which is a major cause of infectious bovine abortion and a significant economic burden to the cattle industry. Definitive hosts are canid and an extensive range of identified susceptible intermediate hosts now includes native Australian species. Pilot experiments demonstrated the high disease susceptibility and the unexpected observation of rapid and prolific cyst formation in the fat-tailed dunnart (Sminthopsis crassicaudata) following inoculation with N. caninum. These findings contrast those in the immunocompetent rodent models and have enormous implications for the role of the dunnart as an animal model to study the molecular host-parasite interactions contributing to cyst formation. An immunohistochemical investigation of the dunnart host cellular response to inoculation with N. caninum was undertaken to determine if a detectable alteration contributes to cyst formation, compared with the eutherian models. Selective cell labelling was observed using novel antibodies developed against Tasmanian devil proteins (CD4, CD8, IgG and IgM) as well as appropriate labelling with additional antibodies targeting T cells (CD3), B cells (CD79b, PAX5), granulocytes, and the monocyte-macrophage family (MAC387). Toluidine blue labelling of mast cells complemented results. Effective labelling was not obtained with CD79a, interleukin-4, interferon-γ, or MHCII antibodies. Descriptions of pathology such as the site and extent of tissue necrosis in S. crassicaudata resemble those reported in immunocompromised rodent models. The exception is the lack of major involvement of the brain and associated neurological signs. Immunohistopathologic findings suggest the dunnart host cell response resembles that described in eutherians – strongly neutrophilic with fewer macrophages focused on sites of tissue necrosis, with a predominantly T cell nature to any lymphoid response inclusive of CD4 positive T helper cells. Intracellular parasite replication is frequently observed in the absence of a detectable host cellular response. More sensitive alternative techniques such as real time polymerase chain reaction using effective cytokine labelling is recommended to further define the host response to neosporosis. Active surveillance of disease to further define the animal model involved collecting cadavers over 28 months from the dunnart colony maintained at the University of Sydney. An additional 66 S. crassicaudata and S. macroura animals were examined. Of the 28.3% of animals diagnosed with a disorder of growth (n=15), 80.0% were diagnosed with a malignancy (n=12), and the most frequently diagnosed neoplasm was squamous cell carcinoma. Lesions were seen on the rostral mandible (2), pouch (2), distal limb (1), and tail (1) and five of six of these tumours were diagnosed in S. macroura. The single squamous cell carcinoma diagnosed in the pouch of an S. crassicaudata showed a distinctive verrucous growth pattern, prompting consideration of a viral causation. Immunohistochemical investigation of carcinomatous proliferations using multiple bovine papillomavirus markers and an antibody targeting the p16 cell protein found no supportive evidence for a viral association. Additional colony pathology included single or multicentric nodular pyogranulomatous or suppurative disease (botryomycosis) – sometimes a comorbidity of carcinoma. In S. crassicaudata eight cases of gastric dilatation were also identified – with and without trichobezoar formation. Collection and examination of specimens from the colony is ongoing

Radiomics in Cross-Sectional Adrenal Imaging: A Systematic Review and Quality Assessment Study

In this study, we aimed to systematically review the current literature on radiomics applied to cross-sectional adrenal imaging and assess its methodological quality. Scopus, PubMed and Web of Science were searched to identify original research articles investigating radiomics applications on cross-sectional adrenal imaging (search end date February 2021). For qualitative synthesis, details regarding study design, aim, sample size and imaging modality were recorded as well as those regarding the radiomics pipeline (e.g., segmentation and feature extraction strategy). The methodological quality of each study was evaluated using the radiomics quality score (RQS). After duplicate removal and selection criteria application, 25 full-text articles were included and evaluated. All were retrospective studies, mostly based on CT images (17/25, 68%), with manual (19/25, 76%) and two-dimensional segmentation (13/25, 52%) being preferred. Machine learning was paired to radiomics in about half of the studies (12/25, 48%). The median total and percentage RQS scores were 2 (interquartile range, IQR = −5–8) and 6% (IQR = 0–22%), respectively. The highest and lowest scores registered were 12/36 (33%) and −5/36 (0%). The most critical issues were the absence of proper feature selection, the lack of appropriate model validation and poor data openness. The methodological quality of radiomics studies on adrenal cross-sectional imaging is heterogeneous and lower than desirable. Efforts toward building higher quality evidence are essential to facilitate the future translation into clinical practice

Mapping the breast cancer metastatic cascade onto ctDNA using genetic and epigenetic clonal tracking.

Circulating tumour DNA (ctDNA) allows tracking of the evolution of human cancers at high resolution, overcoming many limitations of tissue biopsies. However, exploiting ctDNA to determine how a patient's cancer is evolving in order to aid clinical decisions remains difficult. This is because ctDNA is a mix of fragmented alleles, and the contribution of different cancer deposits to ctDNA is largely unknown. Profiling ctDNA almost invariably requires prior knowledge of what genomic alterations to track. Here, we leverage on a rapid autopsy programme to demonstrate that unbiased genomic characterisation of several metastatic sites and concomitant ctDNA profiling at whole-genome resolution reveals the extent to which ctDNA is representative of widespread disease. We also present a methylation profiling method that allows tracking evolutionary changes in ctDNA at single-molecule resolution without prior knowledge. These results have critical implications for the use of liquid biopsies to monitor cancer evolution in humans and guide treatment

Evaluation of novel positron emission tomography radiotracers in humans: tissue distribution kinetics and potential for cancer diagnosis and staging

Positron emission tomography (PET) imaging has emerged as an important decision-making tool in oncology with respect to diagnosis, staging, and assessment of treatment response. We proposed to investigate the ligand binding and retention kinetics of two novel PET/CT tracers in human tumours that do not normally exhibit high [18F]fluorodeoxyglucose ([18F]FDG) uptake, and a third tracer in the context of specific death mechanism. Biological validation of the imaging endpoint included histological correlation with PET/CT data and establishment of an optimum PET/CT methodologies for the probe for implementation into clinical practice. The internal dosimetry and receptor-mediated tumour localisation of the ‘click’ labelled [18F]fluoroethyl triazole octreotate analogue, [18F]FET-βAG-TOCA, in neuroendocrine tumours (NETs) were investigated for the first time in humans. The biomarker demonstrated favourable dosimetry, biodistribution and safety. The calculated effective dose over all subjects (mean ± SD) was 0.029 ± 0.004 mSv/MBq. Regarding staging, [18F]FET-βAG-TOCA PET/CT showed high tumoural uptake with high sensitivity (per lesion) compared with [68Ga]DOTATATE PET/CT (92.8% vs 87.5%). Tissue retention kinetics of the novel choline analogue, [18F]fluoromethyl-[1,2-2H4]- choline ([18F]D4-FCH) were investigated in the staging of muscle invasive bladder cancer (MIBC) and non-small cell lung cancer (NSCLC). The biomarker showed high contrast in lung cancer but poor contrast in bladder cancer. In lung tumours, [18F]D4-FCH uptake was quantitatively lower than [18F]FDG. Pharmacokinetic modelling revealed net tracer influx in tumour consistent with radiotracer phosphorylation via choline kinase, however choline kinase-alpha expression did not correlate with PET parameters. Beyond staging, we evaluated for the first time a caspase-3/7 imaging biomarker, [18F](S)- 1-((1-(2-fluoroethyl)-1H-[1,2,3]-triazol-4-yl)methyl)-5-(2(2,4-difluorophenoxymethyl)- 8 pyrrolidine-1-sulfonyl) ([18F]ICMT-11), for imaging apoptosis and/or necrosis in patients; [18F]FDG-PET is not a marker of caspase-3/7 activation. In breast cancer, lung cancer and lymphoma patients receiving first-line chemotherapy treatment, [18F]ICMT-11 and cytokeratin-18 analysis (blood) were performed. [18F]ICMT-11 showed low uptake pre- and post-chemotherapy in all tumours consistent with unremarkable changes in M30/M60 cytokeratin-18 cleavage products in the breast cohort suggesting a lack of predominantly apoptotic cell death mechanism in responding patients. In lung cancer, multi-parametric [18F]ICMT-11 PET/CT, diffusion weighted (DW-MRI) and dynamic contrast enhanced-MRI (DCE-MRI) showed that PET changes were concordant with cell death in the absence of significant perfusion changes. Thus, tumour response could occur in the absence of predominant chemotherapy-induced caspase-3/7 activation measured non-invasively across entire tumour lesions. In conclusion, the optimal clinical context whereby the [18F]ICMT-11 PET endpoint critically determines the outcome of therapy remains to be established.Open Acces

Molecular genetic investigations of renal cell carcinoma predisposition

Renal Cell Carcinomas (RCC) are a diverse group of histologically and genetically distinct renal neoplasms accounting for 2.4% of all cancers worldwide. While a majority of RCC cases are sporadic in nature, a proportion are due to genetic predisposition caused by syndromic and non-syndromic conditions. Inherited renal cell carcinoma is associated with alterations in genes such as VHL, MET, FH, and FLCN and identification of these genes has been critical to understanding the molecular biology of both inherited and sporadic RCC, informing both clinical management and treatment. Despite the large number of known genes which are linked to RCC predisposition, most individuals with features of RCC predisposition do not harbour variants in known inherited RCC genes, suggesting additional unknown causes of heritability have yet to be uncovered. This study has utilised a range of genomic sequencing methodologies, scaling from single gene to whole genome sequencing, on individuals with features of renal cell carcinoma predisposition in order to identify novel causes of heritability associated with RCC. Multiple genomic sequencing approaches in these individuals has uncovered a range of potential genetic features that could be associated with predisposition to RCC, including genes not previously known to be associated with RCC, discovery of new molecular mechanisms of genetic inheritance for known RCC predisposition syndromes, and provided innovative methods for the identification and characterisation of molecular alterations in specific inherited RCC subtypes