instruction:
Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
question:
Context: The aim of this study was to visualize early stage prostate cancer (Cap) in a clinical setting. In previous studies, the results of magnetic resonance imaging (MRI) for screening Cap have rarely been confirmed by well-designed multisite prostate biopsy.', 'The prostate glands of 90 men with elevated prostate-specific antigen (PSA) were imaged by dynamic contrast-enhanced MRI (DCE-MRI) before transrectal ultrasound-guided 14-cores prostate biopsy. Each core was divided into three subcore fractions (total of 42 fractions) to generate a histological localization diagram, which was compared with localization-visualized DCE-MRI.', "The detection rate of Cap in 57 patients with PSA < 10.0 ng/ml was 36.8% as determined by the initial biopsy. DCE-MRI uncovered 92.9% of the clinically significant Caps and its specificity was 96.2% for the first biopsy session. One case with positive DCE-MRI and a negative primary biopsy was positive with additional biopsies. All of 26 DCE-MRI positive cases had significant Cap, and two of eight patients with histological Cap and negative or equivocal imaging had significant cancer. In total, 9 of 20 cases with DCE-MRI stage T2 underwent radical prostatectomy. All of them had organ-confined disease, although 33-77% (mean 63%) of them were expected to be rated T3 or higher by Partin's table.
Answer: DCE-MRI can identify early stage Cap with high sensitivity and specificity, and can predict the histological grade to some extent. DCE-MRI prior to biopsy should be applied to younger patients with surgical indications. Otherwise, we recommend the definitive diagnosis of Cap by utilizing DCE-MRI alone.
answer:
Is dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI ) a useful modality for the precise detection and staging of early prostate cancer?


question:
Context: Pandemic strains of HIV-1 (group M) encode a total of nine structural (gag, pol, env), regulatory (rev, tat) and accessory (vif, vpr, vpu, nef) genes. However, some subtype A and C viruses exhibit an unusual gene arrangement in which the first exon of rev (rev1) and the vpu gene are placed in the same open reading frame. Although this rev1-vpu gene fusion is present in a considerable fraction of HIV-1 strains, its functional significance is unknown.', 'Examining infectious molecular clones (IMCs) of HIV-1 that encode the rev1-vpu polymorphism, we show that a fusion protein is expressed in infected cells. Due to the splicing pattern of viral mRNA, however, these same IMCs also express a regular Vpu protein, which is produced at much higher levels. To investigate the function of the fusion gene, we characterized isogenic IMC pairs differing only in their ability to express a Rev1-Vpu protein. Analysis in transfected HEK293T and infected CD4+ T cells showed that all of these viruses were equally active in known Vpu functions, such as down-modulation of CD4 or counteraction of tetherin. Furthermore, the polymorphism did not affect Vpu-mediated inhibition of NF-кB activation or Rev-dependent nuclear export of incompletely spliced viral mRNAs. There was also no evidence for enhanced replication of Rev1-Vpu expressing viruses in primary PBMCs or ex vivo infected human lymphoid tissues. Finally, the frequency of HIV-1 quasispecies members that encoded a rev1-vpu fusion gene did not change in HIV-1 infected individuals over time.
Answer: Expression of a rev1-vpu fusion gene does not affect regular Rev and Vpu functions or alter HIV-1 replication in primary target cells. Since there is no evidence for increased replication fitness of rev1-vpu encoding viruses, this polymorphism likely emerged in the context of other mutations within and/or outside the rev1-vpu intergenic region, and may have a neutral phenotype.
answer:
Does a Naturally Occurring rev1-vpu Fusion Gene Confer a Fitness Advantage to HIV-1?


question:
Context: The adaptive immune system seems to play an essential role in the natural course of ovarian cancer. Aim of this study was to establish whether disease-specific survival for patients expressing the tumour antigen p53 is influenced by MHC class I expression or the presence of p53 autoantibodies (p53-Aab).', 'P53 and MHC class I expression were analysed in ovarian cancer tissue of 329 patients by immunohistochemistry using tissue microarrays. For 233 patients, pre-treatment serum samples were available to study the presence of p53 autoantibodies by ELISA. Data were linked to clinicopathological parameters and disease-specific survival.', 'P53 overexpression, MHC class I down-regulation in neoplastic cells and serum p53 autoantibodies were observed in 49.4, 38.9 and 15.9% of patients, respectively. MHC class I down-regulation in p53-overexpressing tumours correlated with a 10-month reduced disease-specific survival in univariate analysis (log-rank 4.10; p=0.043). p53-Aab were strongly correlated with p53 overexpression (p<0.001), but did not influence disease-specific survival.
Answer: As the prognosis of patients with p53-overexpressing ovarian cancer is affected by the MHC class I status of tumour cells and ovarian cancer patients can generate immune responses to the p53 tumour antigen, the further development of immunotherapy should evaluate strategies to improve MHC class I expression by tumour cells to facilitate antigen presentation in an attempt to increase clinical responses.
answer:

Is survival of ovarian cancer patients overexpressing the tumour antigen p53 diminished in case of MHC class I down-regulation?