Publications by authors named "Sarah M Leonard"

To assess the relationship of E2 gene disruption with viral gene expression and clinical outcome in human papillomavirus (HPV) positive head and neck squamous cell carcinoma, we evaluated 31 oropharyngeal and 17 non-oropharyngeal HPV16 positive carcinomas using two PCR-based methods to test for disruption of E2, followed by Sanger sequencing. Expression of HPV16 E6, E7 and E2 transcripts, along with cellular ARF and INK4A, were also assessed by RT-qPCR. Associations between E2 disruption, E2/E6/E7 expression, and clinical outcome were evaluated by Kaplan-Meier analysis for loco-regional recurrence and disease-specific survival.

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The ability to develop a comprehensive panel of treatment predicting factors would significantly improve our ability to stratify patients for cytotoxic or targeted therapies, and prevent patients receiving ineffective treatments. We have investigated if a recently developed genome-wide haploid genetic screen can be used to reveal the critical mediators of response to anticancer therapy. Pancreatic cancer is known to be highly resistant to systemic therapy.

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High-risk human papillomavirus (HR-HPV) causes nearly 100% of cervical carcinoma. However, it remains unclear whether HPV can establish a latent infection, one which may be responsible for the second peak in incidence of cervical carcinoma seen in older women. Therefore, using Ventana in situ hybridisation (ISH), quantitative PCR assays and biomarkers of productive and transforming viral infection, we set out to provide the first robust estimate of the prevalence and characteristics of HPV genomes in FFPE tissue from the cervices of 99 women undergoing hysterectomy for reasons unrelated to epithelial abnormality.

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The current interest in epigenetic priming is underpinned by the belief that remodelling of the epigenetic landscape will sensitise tumours to subsequent therapy. In this pre-clinical study, paediatric AML cells expanded in culture and primary AML xenografts were treated with decitabine, a DNA demethylating agent, and cytarabine, a frontline cytotoxic agent used in the treatment of AML, either alone or in combination. Sequential treatment with decitabine and cytarabine was found to be more effective in reducing tumour burden than treatment with cytarabine alone suggesting that the sequential delivery of these agents may a have real clinical advantage in the treatment of paediatric AML.

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The contribution of early virus-induced epigenetic changes to human papillomavirus (HPV)-associated carcinogenesis is poorly understood. Using genome-wide methylation array profiling and a cell-based model, which supports replication of HPV episomes, we found that transfection of primary human foreskin keratinocytes with episomal forms of high-risk HPV types was followed by upregulation of the DNA methyltransferases, DNMT1 and DNMT3B, and changes in the methylation status of cellular genes many of which are reported to be differentially methylated in cervical neoplasia. HPV16- and HPV18-associated changes were not randomly distributed across the genome, but clustered at specific chromosomal locations which mapped on to known HPV integration sites and to chromosomal regions lost and gained in high-grade cervical neoplasia.

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