MicroRNAs (miRNAs) are noncoding RNAs that regulate expression of target mRNAs and are controlled by tumor suppressors and oncogenes. Altered expression of specific miRNAs in several tumor types and its association with poor prognosis parameters have been reported. Fewer data are available on its impact on patients' survival. We studied the impact of the expression of miR-17-5p, miR-106a, and miR-126 on survival and its correlation with the levels of their target mRNAs and host gene and TP53 alterations. We assessed in 110 colon cancer patients the levels of miR-17-5p, miR-106a, miR-126, E2F1, and EGFL7 by quantitative real-time RT-PCR and loss of heterozygosity (LOH) in the TP53 region. Tumor characteristics, disease-free survival (DFS), and overall survival (OS) were examined in each patient. Altered expression of miR-17-5p, miR-106a, and EGFL7 was associated with pathological tumor features of poor prognosis. Downregulation of miR-106a predicted shortened DFS (P = 0.03) and OS (P = 0.04). miR-17-5p correlated with DFS only at early stages (P = 0.07). Inverse correlations were found between miR-17-5p and miR-106a levels and their target expression, E2F1 (P = 0.04 and P = 0.03, respectively). No correlation was found between miR-126 expression and its host gene levels, EGFL7. miR-106a deregulation was revealed as a marker of DFS and OS independent of tumor stage. The lack of association between expression of miR-126 and its host gene EGFL7 suggests their regulation by independent stimuli. Inverse correlation between miR-17-5p and miR-106a and E2F1 levels supports E2F1 as a target mRNA for the two miRNAs.

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The energy dependence of photofission cross section for heavy nuclei has recently been well described in terms of a Monte Carlo calculation at energies from the pion photoproduction threshold up to 1 GeV [see, for instance, A. Deppman et al., Phys. Rev. Lett. 87 (2001) 182701]. Recent experimental data from CLAS (CEBAF Large Angle Spectrometer) collaboration have extended the measured photofission cross section up to 3.5 GeV for actinide and preactinide nuclei. In this work we address the calculation of photoabsorption and photofission cross sections for actinide and preactinide nuclei above 1 GeV, a region where the shadowing effect plays an important role in the nuclear photoabsorption process. DOI: 10.1103/PhysRevC.73.064607 PACS number(s): 25.20.−x, 25.85.Jg, 24.10.Lx, 24.85.+p Photon-nucleus reactions are excellent tools for investigating nuclear and nucleonic structures. The photonuclear absorption process, for instance, has been used to study the formation and propagation of baryonic resonances inside nuclear matter [1-6], the photon hadronization process that gives rise to the shadowing effect in the photoabsorption cross section [1,7], or the formation and propagation of hyperons in the nucleus [6]. The simplicity of photonuclear reactions as compared to reactions induced by other probes, from both the theoretical and experimental points of view, is attractive to those willing to study nuclear and subnuclear structures.However, the various nuclear processes taking place during the reaction, mainly at intermediate and high energies, cause some problems in the comprehension of the nuclear or subnuclear mechanisms. One example is the fissility of heavy nuclei. It was supposed that fissility was an increasing function of the photon energy, and that for actinide nuclei, which present the highest fissility values among the stable nuclei, one could expect their fissility to be 1 for energies above a few hundred MeV [8]. In fact, the measurement of fission cross section was proposed as a reliable method for measuring the total photoabsorption cross section [9,10]. A fine, although incomplete, overview on the theoretical approaches for calculating photofission cross sections is presented in Ref. [11].Experimental results obtained at Frascati [9,10], Mainz [12,13], Bonn [1,14], Saskatoon [15], and Thomas Jefferson Laboratory [16,17] have shown, however, that this was not the case. The fissility for thorium and several uranium isotopes was found to be lower than that for neptunium, showing that nuclear fissility does not saturate for those nuclei, remaining at a value below 100% even at high incident photon energies. This result was fully explained by a Monte Carlo study of the intranuclear cascade and evaporation/fission competition processes that follows the photon absorption, as implemented by the MCMC and MCEF codes [18,19]. The important feature for explaining the nonsaturation of the heavy-nuclei fissility was the inclusion of protons and α-particles evaporation in the evaporation-fission competition proc...

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