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Item does not contain fulltext, Cell-free DNA in the blood provides a non-invasive diagnostic avenue for patients with cancer(1). However, characteristics of the origins and molecular features of cell-free DNA are poorly understood. Here we developed an approach to evaluate fragmentation patterns of cell-free DNA across the genome, and found that profiles of healthy individuals reflected nucleosomal patterns of white blood cells, whereas patients with cancer had altered fragmentation profiles. We used this method to analyse the fragmentation profiles of 236 patients with breast, colorectal, lung, ovarian, pancreatic, gastric or bile duct cancer and 245 healthy individuals. A machine learning model that incorporated genome-wide fragmentation features had sensitivities of detection ranging from 57% to more than 99% among the seven cancer types at 98% specificity, with an overall area under the curve value of 0.94. Fragmentation profiles could be used to identify the tissue of origin of the cancers to a limited number of sites in 75% of cases. Combining our approach with mutation-based cell-free DNA analyses detected 91% of patients with cancer. The results of these analyses highlight important properties of cell-free DNA and provide a proof-of-principle approach for the screening, early detection and monitoring of human cancer.

Contains fulltext : 168862.pdf (publisher's version ) (Open Access)

Oncogenic stimuli trigger the DNA damage response (DDR) and induction of the alternative reading frame (ARF) tumor suppressor, both of which can activate the p53 pathway and provide intrinsic barriers to tumor progression. However, the respective timeframes and signal thresholds for ARF induction and DDR activation during tumorigenesis remain elusive. Here, these issues were addressed by analyses of mouse models of urinary bladder, colon, pancreatic and skin premalignant and malignant lesions. Consistently, ARF expression occurred at a later stage of tumor progression than activation of the DDR or p16 , a tumor-suppressor gene overlapping with ARF. Analogous results were obtained in several human clinical settings, including early and progressive lesions of the urinary bladder, head and neck, skin and pancreas. Mechanistic analyses of epithelial and fibroblast cell models exposed to various oncogenes showed that the delayed upregulation of ARF reflected a requirement for a higher, transcriptionally based threshold of oncogenic stress, elicited by at least two oncogenic 'hits', compared with lower activation threshold for DDR. We propose that relative to DDR activation, ARF provides a complementary and delayed barrier to tumor development, responding to more robust stimuli of escalating oncogenic overload.

INTRODUCTION: The mast cell lives a hidden life, but it is implicated in several physiological reactions. Its ability to react to different stimuli impacts a variety of conditions such as asthma, atopic dermatitis, urticaria and anaphylaxis. It is not until recent decades that the evolution of the cell has been described and its fascinating biology has only recently been depicted. We here give a review of systemic mastocytosis in regards to cell biology, diagnostic approaches and clinical practice. METHODS: A search was made in PubMed in August 2011 entering the keywords: mastocytosis, (systemic, cutaneous, aggressive), mast cell leukaemia, mast cell sarcoma, chromosome, mutation, haematology and treatment. RESULTS: Mastocytosis is characterized by an abnormal proliferation of mast cells, which accumulate in one or several organ systems, primarily the skin and bone marrow. The disease is clinically heterogeneous and varies from a relatively benign condition with isolated cutaneous lesions to a very aggressive systemic condition with a grave prognosis. The condition affects men and women equally. Children are especially affected by the cutaneous form. In most children, the condition will improve or remit spontaneously before adulthood. Mastocytosis in adults, however, is more often systemic and tends to persist. CONCLUSION: Patients with mastocytosis represent a hetero geneous group in terms of clinical presentation, management and prognosis. Furthermore, a range of medical specialties serve as the primary entrance to health services, which can be a challenge in respect of achieving uniform management. In order to improve diagnostics and management of systemic mastocytosis, the European Competence Network on Mastocytosis has been established. Patients under suspicion of systemic mastocytosis should be conferred with or referred to a haematological and a dermatological/ allergological department.

Somatic mutations of the two genes coding for the histone acetyltransferase genes, CREEBP and EP300 have been identified as a pathogenetic mechanism shared by common forms of B-cell non-Hodgkinós lymphomas. A screening for somatic mutations in CREEBP and EP300 genes in patients with myeloproliferative neoplasms (MPNs) has not previously been performed. DNA was purified from diagnostic samples of 56 MPN patients. We designed a mutation screening assay based on denaturing gradient gel electrophoresis and direct sequencing. Our results suggest that CREBBP and EP300 mutations are not major pathogenetic mechanisms of MPNs. The rationale for using HDACi in these patients seems reasonable.

Udgivelsesdato: 2008/8/1