32 research outputs found

    A common functional consequence of tumor-derived mutations within c-MYC

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    The relevance of changes to the coding sequence of the c-MYC oncogene to malignancy is controversial. Overexpression of a pristine form of MYC is observed in many cancers and is sufficient to drive tumorigenesis in most contexts. Yet missense changes to MYC are found in ~50% of Burkitt's lymphomas, aggregate within an amino-terminal degron important for proteasomal destruction of MYC, and where examined profoundly enhance the tumorigenic properties of MYC in vitro and in vivo. Much of the controversy surrounding these mutants stems from the limited number of mutations that have been evaluated and their clustering within a single region of the MYC protein; the highly-conserved Myc box I (MbI) element. Here, by analysis of extant genomic data sets, we identify a previously unrecognized hotspot for tumor-associated MYC mutations, located in a conserved central portion of the protein. We show that, despite their distal location in MYC, mutations in this region precisely phenocopy those in MbI in terms of stability, in vitro transformation, growth-promoting properties, in vivo tumorigenesis and ability to escape p53-dependent tumor surveillance mechanisms. The striking parallels between the behavior of tumor-derived mutations in disparate regions of the MYC protein reveals that a common molecular process is disrupted by these mutations, implying an active role for these mutations in tumorigenesis and suggesting that different therapeutic strategies may be needed for treatment of lymphomas expressing wild type versus mutant forms of MYC protein.Oncogene advance online publication, 7 July 2014; doi:10.1038/onc.2014.186

    The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake

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    Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na+-rich animal and nutrition for the plant

    Improving American Healthcare Through Clinical Lab 20 : A Project Santa Fe Report

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    Project Santa Fe was established both to provide thought leadership and to help develop the evidence base for the valuation of clinical laboratory services in the next era of American healthcare. The participants in Project Santa Fe represent major regional health systems that can operationalize laboratory-driven innovations and test their valuation in diverse regional marketplaces in the United States. We provide recommendations from the inaugural March 2016 meeting of Project Santa Fe. Specifically, in the transition from volume-based to value-based health care, clinical laboratories are called upon to provide programmatic leadership in reducing total cost of care through optimization of time-to-diagnosis and time-to-effective therapeutics, optimization of care coordination, and programmatic support of wellness care, screening, and monitoring. This call to action is more than working with industry stakeholders on the basis of our expertise; it is providing leadership in creating the programs that accomplish these objectives. In so doing, clinical laboratories can be effectors in identifying patients at risk for escalation in care, closing gaps in care, and optimizing outcomes of health care innovation. We also hope that, through such activities, the evidence base will be created for the new value propositions of integrated laboratory networks. In the very simplest sense, this effort to create Clinical Lab 2.0 will establish the impact of laboratory diagnostics on the full 100% spend in American healthcare, not just the 2.5% spend attributed to in vitro diagnostics. In so doing, our aim is to empower regional and local laboratories to thrive under new models of payment in the next era of American health care delivery

    A comparison of human papillomavirus genotype-specific DNA and E6/E7 mRNA detection to identify anal precancer among HIV-infected men who have sex with men.

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    BackgroundHuman papillomavirus (HPV) RNA detection is reportedly more specific for the detection of anogenital precancer than HPV DNA but it is unknown whether this is due to detection of RNA or due to HPV genotype restriction.MethodsA total of 363 human immunodeficiency virus (HIV)-positive men who have sex with men had two anal cytology samples taken and were evaluated using high-resolution anoscopy and biopsies of visible lesions. Anal specimens were tested for E6/E7 RNA for five carcinogenic HPV genotypes (HPV16, 18, 31, 33, and 45) and tested for the DNA of 13 carcinogenic HPV genotypes.ResultsDNA testing was more likely to be positive than RNA testing (53% vs. 48%; P = 0.02) for the same five HPV genotypes in aggregate. When restricted to five HPV genotypes targeted by the RNA test, the sensitivity to detect anal precancer was the same for DNA and RNA (81%), whereas RNA was more specific than DNA (65% vs. 58%; P = 0.007). In comparison, DNA detection of all 13 carcinogenic HPV genotypes was more sensitive (96% vs. 81%; P = 0.001) but much less specific (65% vs. 33%; P < 0.001) as compared with RNA detection of the five HPV genotypes.ConclusionAfter controlling for HPV genotypes, RNA was only slightly more specific than DNA detection for anal precancer.ImpactDNA or RNA testing for a subset of the most carcinogenic HPV genotypes may be useful for distinguishing between those HPV-positive men at higher and lower risk of anal precancer and cancer

    Human papillomavirus genotyping, human papillomavirus mRNA expression, and p16/Ki-67 cytology to detect anal cancer precursors in HIV-infected MSM.

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    ObjectiveAnal cancer incidence is high in HIV-infected MSM. Screening for anal intraepithelial lesions and cancers is performed at specialized clinics and relies on high-resolution anoscopy (HRA) and anal cytology. Both approaches have limited reproducibility and sensitivity for detecting anal cancer precursors. We evaluated biomarkers for human papillomavirus (HPV)-related disease in a population of HIV-infected MSM.MethodsA cross-sectional screening study with passive follow-up included 363 MSM followed at a HIV/AIDS clinic. All men had anal cytology samples taken and were evaluated using HRA and anal biopsies. Using a composite endpoint of biopsy results and cytology, we compared the performance of HPV16/18 genotyping, HPVE6/E7 mRNA expression, and p16/Ki-67 cytology to detect high-grade anal intraepithelial neoplasias (AINs).ResultsFor all biomarkers analyzed, there was a significant trend of increasing percentage of men testing positive with increasing severity of disease (P < 0.001). HPV DNA testing had the highest sensitivity for anal intraepithelial neoplasia grade 2 and anal intraepithelial neoplasia grade 3 (AIN3), followed by p16/Ki-67, HPVE6/E7 mRNA testing, and HPV16/18 genotyping. The highest Youden's index was observed for HPVE6/E7 mRNA testing, followed by HPV16/18 genotyping, p16/Ki-67 cytology, and HPV DNA testing. Increasing the threshold for positivity of p16/Ki-67 to five or more positive cells led to significantly higher specificity, but unchanged sensitivity for detecting AIN3.ConclusionMolecular features of anal disease categories are similar to those of corresponding cervical lesions. Biomarkers evaluated for cervical cancer screening may be used for primary anal cancer screening or to decide who should require immediate treatment vs. expectant management

    Risk factors for anal HPV infection and anal precancer in HIV-infected men who have sex with men.

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    BackgroundCarcinogenic human papillomaviruses (HPVs) cause a large proportion of anal cancers. Human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) are at increased risk of HPV infection and anal cancer compared with HIV-negative men. We evaluated risk factors for HPV infection and anal precancer in a population of HIV-infected MSM.MethodsOur study included 305 MSM at an HIV/AIDS clinic in the Kaiser Permanente Northern California Health Maintenance Organization. Logistic regression was used to estimate associations of risk factors comparing men without anal HPV infection; men with anal HPV infection, but no precancer; and men with anal precancer.ResultsLow CD4 count (<350 cells/mm(3)) and previous chlamydia infection were associated with an increased risk of carcinogenic HPV infection (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.28-10.40 and OR, 4.24; 95% CI, 1.16-15.51, respectively). History of smoking (OR, 2.71 95% CI, 1.43-5.14), duration, recency, and dose of smoking increased the risk of anal precancer among carcinogenic HPV-positive men but had no association with HPV infection.ConclusionsWe found distinct risk factors for anal HPV infection and anal precancer. Risk factors for HPV infection and anal precancer are similar to established risk factors for cervical cancer progression
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