Sir Peter MacCallum Department of Oncology - Research Publications
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ItemNo Preview AvailableGata-3 Negatively Regulates the Tumor-Initiating Capacity of Mammary Luminal Progenitor Cells and Targets the Putative Tumor Suppressor Caspase-14(AMER SOC MICROBIOLOGY, 2011-11)The transcription factor Gata-3 is a definitive marker of luminal breast cancers and a key regulator of mammary morphogenesis. Here we have explored a role for Gata-3 in tumor initiation and the underlying cellular mechanisms using a mouse model of "luminal-like" cancer. Loss of a single Gata-3 allele markedly accelerated tumor progression in mice carrying the mouse mammary tumor virus promoter-driven polyomavirus middle T antigen (MMTV-PyMT mice), while overexpression of Gata-3 curtailed tumorigenesis. Through the identification of two distinct luminal progenitor cells in the mammary gland, we demonstrate that Gata-3 haplo-insufficiency increases the tumor-initiating capacity of these progenitors but not the stem cell-enriched population. Overexpression of a conditional Gata-3 transgene in the PyMT model promoted cellular differentiation and led to reduced tumor-initiating capacity as well as diminished angiogenesis. Transcript profiling studies identified caspase-14 as a novel downstream target of Gata-3, in keeping with its roles in differentiation and tumorigenesis. A strong association was evident between GATA-3 and caspase-14 expression in preinvasive ductal carcinoma in situ samples, where GATA-3 also displayed prognostic significance. Overall, these studies identify GATA-3 as an important regulator of tumor initiation through its ability to promote the differentiation of committed luminal progenitor cells.
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ItemEstrogen Receptor β Activation Impairs Prostatic Regeneration by Inducing Apoptosis in Murine and Human Stem/Progenitor Enriched Cell Populations(PUBLIC LIBRARY SCIENCE, 2012-07-10)Androgen depletion is the primary treatment for prostate disease; however, it fails to target residual castrate-resistant cells that are regenerative and cells of origin of prostate cancer. Estrogens, like androgens, regulate survival in prostatic cells, and the goal of this study was to determine the advantages of selective activation of estrogen receptor β (ERβ) to induce cell death in stem cells that are castrate-resistant. Here we show two cycles of short-term ERβ agonist (8β-VE2) administration this treatment impairs regeneration, causing cystic atrophy that correlates with sustained depletion of p63+ basal cells. Furthermore, agonist treatment attenuates clonogenicity and self-renewal of murine prostatic stem/progenitor cells and depletes both murine (Lin(-)Sca1(+)CD49f(hi)) and human (CD49f(hi)Trop2(hi)) prostatic basal cells. Finally, we demonstrate the combined added benefits of selective stimulation of ERβ, including the induction of cell death in quiescent post-castration tissues. Subsequent to castration ERβ-induces further apoptosis in basal, luminal and intermediate cells. Our results reveal a novel benefit of ERβ activation for prostate disease and suggest that combining selective activation of ERβ with androgen-deprivation may be a feasible strategy to target stem cells implicated in the origin of prostatic disease.
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ItemKnowledge, attitudes and practices of health professionals and women towards medication use in breastfeeding: A review.(Springer Science and Business Media LLC, 2011-08-26)Many breastfeeding women require and regularly take medicines, especially those available over-the-counter, and the safe use of these is dependent on the advice provided by health professionals such as general practitioners and pharmacists. The primary aim of this review therefore, was to investigate the literature relating to health professionals' and women's knowledge, attitudes and practices towards medication use and safety in breastfeeding. The limited literature that was uncovered identified that general practitioners and pharmacists have poor knowledge, but positive attitudes, and variable practices that are mostly guided by personal experience. They tend to make decisions about the use of a medicine whilst breastfeeding based on the potential 'risk' that it poses to the infant in terms of possible adverse reactions, rather than its 'compatibility' with breast milk. The decision-making process between health professionals and women is usually not a negotiated process, and women are often asked to stop breastfeeding whilst taking a medicine. Women, in turn, are left dissatisfied with the advice received, many choosing not to initiate therapy or not to continue breastfeeding. Some directions for future research have been suggested to address the issues identified in this critical area. This review is important from a societal perspective because many breastfeeding women require and regularly take medications, especially those available without prescription, and the safe use of these is dependent on the advice provided by health professionals, which is ultimately influenced by their knowledge, attitudes and practices. However, there is an absence of high quality evidence from randomised controlled trials on the safety of medications taken during breastfeeding, which naturally would hinder health professionals from appropriately advising women. It is equally important to know about women's experiences of advice received from health professionals, and whether there is consistency between recommendations made across resources on medication safety in breastfeeding, in order to gain a full understanding of the issues prevalent in this area of practice.
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ItemPiloting the role of a pharmacist in a community palliative care multidisciplinary team: an Australian experience.(Springer Science and Business Media LLC, 2011-10-31)BACKGROUND: While the home is the most common setting for the provision of palliative care in Australia, a common problem encountered here is the inability of patient/carers to manage medications, which can lead to misadventure and hospitalisation. This can be averted through detection and resolution of drug related problems (DRPs) by a pharmacist; however, they are rarely included as members of the palliative care team. The aim of this study was to pilot a model of care that supports the role of a pharmacist in a community palliative care team. A component of the study was to develop a cost-effective model for continuing the inclusion of a pharmacist within a community palliative care service. METHODS: The study was undertaken (February March 2009-June 2010) in three phases. Development (Phase 1) involved a literature review; scoping the pharmacist's role; creating tools for recording DRPs and interventions, a communication and education strategy, a care pathway and evidence based patient information. These were then implemented in Phase 2. Evaluation (Phase 3) of the impact of the pharmacist's role from the perspectives of team members was undertaken using an online survey and focus group. Impact on clinical outcomes was determined by the number of patients screened to assess their risk of medication misadventure, as well as the number of medication reviews and interventions performed to resolve DRPs. RESULTS: The pharmacist screened most patients (88.4%, 373/422) referred to the palliative care service to assess their risk of medication misadventure, and undertook 52 home visits. Medication reviews were commonly conducted at the majority of home visits (88%, 46/52), and a variety of DRPs (113) were detected at this point, the most common being "patient requests drug information" (25%, 28/113) and "condition not adequately treated" (22%, 25/113). The pharmacist made 120 recommendations in relation to her interventions.Fifty percent of online survey respondents (10/20) had interacted 10 or more times with the pharmacist for advice. All felt that the pharmacist's role was helpful, improving their knowledge of the different medications used in palliative care. The six team members who participated in the focus group indicated that there were several benefits of the pharmacist's contributions towards medication screening and review. CONCLUSIONS: The inclusion of a pharmacist in a community palliative care team lead to an increase in the medication-related knowledge and skills of its members, improved patients' medication management, and minimised related errors. The model of care created can potentially be duplicated by other palliative care services, although its cost-effectiveness was unable to be accurately tested within the study.
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ItemExploiting the noise: improving biomarkers with ensembles of data analysis methodologies(BMC, 2012-11-12)BACKGROUND: The advent of personalized medicine requires robust, reproducible biomarkers that indicate which treatment will maximize therapeutic benefit while minimizing side effects and costs. Numerous molecular signatures have been developed over the past decade to fill this need, but their validation and up-take into clinical settings has been poor. Here, we investigate the technical reasons underlying reported failures in biomarker validation for non-small cell lung cancer (NSCLC). METHODS: We evaluated two published prognostic multi-gene biomarkers for NSCLC in an independent 442-patient dataset. We then systematically assessed how technical factors influenced validation success. RESULTS: Both biomarkers validated successfully (biomarker #1: hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.21 to 2.19, P = 0.001; biomarker #2: HR 1.42, 95% CI 1.03 to 1.96, P = 0.030). Further, despite being underpowered for stage-specific analyses, both biomarkers successfully stratified stage II patients and biomarker #1 also stratified stage IB patients. We then systematically evaluated reasons for reported validation failures and find they can be directly attributed to technical challenges in data analysis. By examining 24 separate pre-processing techniques we show that minor alterations in pre-processing can change a successful prognostic biomarker (HR 1.85, 95% CI 1.37 to 2.50, P < 0.001) into one indistinguishable from random chance (HR 1.15, 95% CI 0.86 to 1.54, P = 0.348). Finally, we develop a new method, based on ensembles of analysis methodologies, to exploit this technical variability to improve biomarker robustness and to provide an independent confidence metric. CONCLUSIONS: Biomarkers comprise a fundamental component of personalized medicine. We first validated two NSCLC prognostic biomarkers in an independent patient cohort. Power analyses demonstrate that even this large, 442-patient cohort is under-powered for stage-specific analyses. We then use these results to discover an unexpected sensitivity of validation to subtle data analysis decisions. Finally, we develop a novel algorithmic approach to exploit this sensitivity to improve biomarker robustness.
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ItemParaneoplastic leukocytoclastic vasculitis as an initial presentation of malignant pleural mesothelioma: a case report.(Springer Science and Business Media LLC, 2012-08-31)INTRODUCTION: Vasculitis has been associated with malignancies, more commonly hematological rather than solid malignancies. Due to the rarity of these conditions and the lack of a temporal association, the relationship between vasculitis and malignancy remains unclear. Paraneoplastic vasculitis as a phenomenon of lung cancer has been described in the literature. To the best of our knowledge, this is the first case report of leukocytoclastic vasculitis being an initial presentation of malignant pleural mesothelioma. CASE PRESENTATION: We report the case of an 84-year old Greek man who presented to our facility with an erythematous, pruritic and purpuric rash affecting his limbs. This was biopsy-proven to be leukocytoclastic vasculitis and treated conservatively with topical corticosteroids as well as oral prednisolone, with good results. Six months later, he was diagnosed as having malignant pleural mesothelioma. As he remained asymptomatic from his malignancy, no systemic chemotherapy was instituted. He had a recurrence of biopsy-proven leukocytoclastic vasculitis two months after he was diagnosed as having mesothelioma, which again settled with conservative measures. CONCLUSIONS: It is important to remain vigilant with regard to the association between leukocytoclastic vasculitis and malignancies. A diagnosis of vasculitis requires a search for malignancies as well as other possible etiologies. This is particularly of relevance when the vasculitis becomes chronic, recurrent or treatment is no longer effective. Should our patient have experienced refractory vasculitis, we would have instituted systemic chemotherapy to treat the underlying malignancy.
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ItemMultiple functions of CXCL12 in a syngeneic model of breast cancer(BMC, 2010-09-17)BACKGROUND: A growing body of work implicates chemokines, in particular CXCL12 and its receptors, in the progression and site-specific metastasis of various cancers, including breast cancer. Various agents have been used to block the CXCL12-CXCR4 interaction as a means of inhibiting cancer metastasis. However, as a potent chemotactic factor for leukocytes, CXCL12 also has the potential to enhance anti-cancer immunity. To further elucidate its role in breast cancer progression, CXCL12 and its antagonist CXCL12(P2G) were overexpressed in the syngeneic 4T1.2 mouse model of breast carcinoma. RESULTS: While expression of CXCL12(P2G) significantly inhibited metastasis, expression of wild-type CXCL12 potently inhibited both metastasis and primary tumor growth. The effects of wild-type CXCL12 were attributed to an immune response characterized by the induction of CD8+ T cell activity, enhanced cell-mediated cytotoxicity, increased numbers of CD11c+ cells in the tumor-draining lymph nodes and reduced accumulation of myeloid-derived suppressor cells in the spleen. CONCLUSIONS: This study highlights the need to consider carefully therapeutic strategies that block CXCL12 signaling. Therapies that boost CXCL12 levels at the primary tumor site may prove more effective in the treatment of metastatic breast cancer.
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ItemIdentifying a High Fraction of the Human Genome to be under Selective Constraint Using GERP plus(PUBLIC LIBRARY SCIENCE, 2010-12)Computational efforts to identify functional elements within genomes leverage comparative sequence information by looking for regions that exhibit evidence of selective constraint. One way of detecting constrained elements is to follow a bottom-up approach by computing constraint scores for individual positions of a multiple alignment and then defining constrained elements as segments of contiguous, highly scoring nucleotide positions. Here we present GERP++, a new tool that uses maximum likelihood evolutionary rate estimation for position-specific scoring and, in contrast to previous bottom-up methods, a novel dynamic programming approach to subsequently define constrained elements. GERP++ evaluates a richer set of candidate element breakpoints and ranks them based on statistical significance, eliminating the need for biased heuristic extension techniques. Using GERP++ we identify over 1.3 million constrained elements spanning over 7% of the human genome. We predict a higher fraction than earlier estimates largely due to the annotation of longer constrained elements, which improves one to one correspondence between predicted elements with known functional sequences. GERP++ is an efficient and effective tool to provide both nucleotide- and element-level constraint scores within deep multiple sequence alignments.
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ItemScreening participation for people at increased risk of colorectal cancer due to family history: a systematic review and meta-analysis(SPRINGER, 2013-09)We conducted a systematic review and a meta-analysis of observational studies to identify and summarise the level of colorectal cancer (CRC) screening participation for people at increased risk due to family history of the disease. Medline, Cinhal, Embase and PsychInfo databases were comprehensively searched between January 1995 and May 2012 to identify relevant articles. To be included, studies had to report on screening for people who had at least one first-degree relative with CRC and no previous personal diagnosis of the disease. Pooled screening participation levels were calculated for each screening modality. Seventeen studies, accounting for a total of 13,269 subjects with a family history of CRC met the inclusion criteria. Seven studies, including a total of 6,901 subjects had a pooled faecal occult blood testing screening participation (at least once) of 25 % (95 % CI 12-38). Five studies including a total of 5,091 subjects had a pooled sigmoidoscopy-based screening participation (at least once) of 16 % (95 % CI 7-27). Seven studies including a total of 9,965 subjects had pooled participation colonoscopy-based screening (at least once) of 40 % (95 % CI 26-54). There was a significant level of screening heterogeneity between studies. This review identified a substantial underuse of CRC screening for people at increased risk of developing the disease. It highlights the potential opportunity that exists for increasing screening participation among this segment of the population and the need to adjust the current CRC screening policies towards that objective.
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ItemSuboptimal health literacy in patients with lung cancer or head and neck cancer(SPRINGER, 2013-08)BACKGROUND: Health literacy is the capacity to seek, understand and utilise health information to make informed health decisions. Suboptimal health literacy has been linked to poor health outcomes. This study assessed health literacy in patients treated for head and neck or lung cancer and associations between health literacy and demographic factors and distress levels. METHODS: Consecutive English-speaking patients were approached at Peter MacCallum Cancer Centre. Face-to-face interviews were conducted. Health literacy was assessed using the Shortened Test of Functional Health Literacy in Adults (S-TOFHLA) and Health Literacy Management Scale (HeLMS). Distress was assessed by the Distress Thermometer. RESULTS: Response rate was 73 % (n = 93). Using S-TOFHLA, prevalence of inadequate and marginal health literacy was 5.4 and 6.5 % respectively, and both groups were associated with older age (p = 0.043) and low education level (p = 0.009). Specific assessment of S-TOFHLA revealed that 70 % could not interpret prescription labels. HeLMS reported that 17 % had health literacy difficulties. Low scores on domains of HeLMS were associated with lower education level (p < 0.05) but younger age (p < 0.05). Distress was not associated with S-TOFHLA scores but related to low scores in two domains of HeLMS (p < 0.05). CONCLUSION: Using two different measures, a substantial proportion of patients have poor health literacy abilities and may experience difficulties in accessing health services.