Constraining the Nature of Dark Energy using the SKA

We investigate the potential of the Square Kilometer Array Telescope (SKA) to constrain the sound speed of dark energy. The Integrated Sachs Wolfe (ISW) effect results in a significant power spectrum signal when CMB temperature anisotropies are cross-correlated with galaxies detectable with the SKA in HI. We consider using this measurement, the autocorrelation of HI galaxies and the CMB temperature power spectrum to derive constraints on the sound speed. We study the contributions to the cross-correlation signal made by galaxies at different redshifts and use redshift tomography to improve the signal-to-noise. We use a chi-square analysis to estimate the significance of detecting a sound speed different from that expected in quintessence models, finding that there is potential to distinguish very low sound speeds from the quintessence value.Comment: 8 pages, 8 figures; updated references for publication MNRA

Comprehensive molecular characterization of the hippo signaling pathway in cancer

Hippo signaling has been recognized as a key tumor suppressor pathway. Here, we perform a comprehensive molecular characterization of 19 Hippo core genes in 9,125 tumor samples across 33 cancer types using multidimensional “omic” data from The Cancer Genome Atlas. We identify somatic drivers among Hippo genes and the related microRNA (miRNA) regulators, and using functional genomic approaches, we experimentally characterize YAP and TAZ mutation effects and miR-590 and miR-200a regulation for TAZ. Hippo pathway activity is best characterized by a YAP/TAZ transcriptional target signature of 22 genes, which shows robust prognostic power across cancer types. Our elastic-net integrated modeling further reveals cancer-type-specific pathway regulators and associated cancer drivers. Our results highlight the importance of Hippo signaling in squamous cell cancers, characterized by frequent amplification of YAP/TAZ, high expression heterogeneity, and significant prognostic patterns. This study represents a systems-biology approach to characterizing key cancer signaling pathways in the post-genomic era

Updated trends in imaging use in men diagnosed with prostate cancer

Background:Previous studies have found persistent overuse of imaging for clinical staging of men with low-risk prostate cancer. We aimed to determine imaging trends in three cohorts of men.Methods:We analyzed imaging trends of men with prostate cancer who were a part of Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) (1998-2006), were insured by Medicare (1998-2006), or privately insured (Ingenix database, 2002-2006). The rates of computed tomography (CT), magnetic resonance imaging (MRI) and bone scan (BS) were determined and time trends were analyzed by linear regression. For men in CaPSURE, demographic and clinical predictors of test use were explored using a multivariable regression model.Results:Since 1998, there was a significant downward trend in BS (16%) use in the CaPSURE cohort (N=5156). There were slight downward trends (2.4 and 1.7%, respectively) in the use of CT and MRI. Among 54 322 Medicare patients, BS, CT and MRI use increased by 2.1, 10.8 and 2.2% and among 16 161 privately insured patients, use increased by 7.9, 8.9 and 3.7%, respectively. In CaPSURE, the use of any imaging test was greater in men with higher-risk disease. In addition, type of insurance and treatment affected the use of imaging tests in this population.Conclusions:There is widespread misuse of imaging tests in men with low-risk prostate cancer, particularly for CT. These findings highlight the need for examination of factors that drive decision making with respect to imaging in this setting. © 2014 Macmillan Publishers Limited

Updated trends in imaging use in men diagnosed with prostate cancer

Background:Previous studies have found persistent overuse of imaging for clinical staging of men with low-risk prostate cancer. We aimed to determine imaging trends in three cohorts of men.Methods:We analyzed imaging trends of men with prostate cancer who were a part of Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) (1998-2006), were insured by Medicare (1998-2006), or privately insured (Ingenix database, 2002-2006). The rates of computed tomography (CT), magnetic resonance imaging (MRI) and bone scan (BS) were determined and time trends were analyzed by linear regression. For men in CaPSURE, demographic and clinical predictors of test use were explored using a multivariable regression model.Results:Since 1998, there was a significant downward trend in BS (16%) use in the CaPSURE cohort (N=5156). There were slight downward trends (2.4 and 1.7%, respectively) in the use of CT and MRI. Among 54 322 Medicare patients, BS, CT and MRI use increased by 2.1, 10.8 and 2.2% and among 16 161 privately insured patients, use increased by 7.9, 8.9 and 3.7%, respectively. In CaPSURE, the use of any imaging test was greater in men with higher-risk disease. In addition, type of insurance and treatment affected the use of imaging tests in this population.Conclusions:There is widespread misuse of imaging tests in men with low-risk prostate cancer, particularly for CT. These findings highlight the need for examination of factors that drive decision making with respect to imaging in this setting. © 2014 Macmillan Publishers Limited