Given a passage, 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.

Example Input: To identify a biomarker of ovarian cancer response to chemotherapy. PATIENTS AND METHODS Study: participants had epithelial ovarian cancer treated with surgery followed by platinum-based chemotherapy. DNA and RNA were isolated from frozen tumors and normal DNA was isolated from matched peripheral blood. A whole-genome loss of heterozygosity (LOH) analysis was performed using a high-density oligonucleotide array. Candidate genomic areas that predicted enhanced response to chemotherapy were identified with Cox proportional hazards methods. Gene expression analyses were performed through microarray experiments. Candidate genes were tested for independent effects on survival using Cox proportional hazards models, Kaplan-Meier survival curves, and the log-rank test.', 'Using a whole-genome approach to study the molecular determinants of ovarian cancer response to platinum-based chemotherapy, we identified LOH of a 13q region to predict prolonged progression-free survival (PFS; hazard ratio, 0.23; P = .006). ERCC5 was identified as a candidate gene in this region because of its known function in the nucleotide excision repair pathway, the unique DNA repair pathway that removes platinum-DNA adducts. We found LOH of the ERCC5 gene locus and downregulation of ERCC5 gene expression to predict prolonged PFS. Integration of genomic and gene expression data shows a correlation between 13q LOH and ERCC5 gene downregulation.
Example Output: Is eRCC5 a novel biomarker of ovarian cancer prognosis?

Example Input: Changes of volume status can be readily inferred from variations in diameter of the inferior vena cava (IVC) measured by ultrasound. However the effect of IVC changes following acute blood loss are not fully established. In this study, three different approaches to measuring IVC variables were compared in healthy blood donors, as a model of acute volume depletion, in order to establish their relative ability to detect acute blood loss.', 'Inspiratory and expiratory IVC diameters were measured before and after blood donation in hepatic long axis, hepatic short axis and renal short axis views using a 2-5\xa0MHz curvilinear probe. All measurements were recorded and examined in real-time and post-processing sessions.', 'All windows performed satisfactorily but the renal window approach was feasible in only 30 out of 47 subjects. After blood donation, IVC diameters decreased in hepatic long axis, hepatic short axis and renal short axis (expiratory: -19.9, -18.0, -26.5\xa0%; CI 95\xa0%: 14.5-24.1; 13.1-22.9; 16.0-35.9, respectively) (inspiratory: -31.1, -31.6, -36.5\xa0%; CI 95\xa0%: 21.3-40.1; 18.8-45.2; 23.4-46.0, respectively), whereas the IVC collapsibility index increased by 21.6, 22.6 and 19.3\xa0% (CI 95\xa0%: 11.6-42.9; 18.5-39.5; 7.7-30.0). IVC diameters appeared to return to pre-donation values within 20\xa0min but this was only detected by the hepatic long axis view.
Example Output: Do inferior vena cava diameters and collapsibility index reveal early volume depletion in a blood donor model?

Example Input: Preoperative chemoradiotherapy is one of the key strategies for the improvement of survival in pancreatic cancer; however, no method to predict the response has yet been established. The aim of this study was to prospectively evaluate the predictive value of REG4, a new member of the regenerating (REG) islet-derived family of proteins.', 'Stably REG4-expressing cells were established from a pancreatic cancer cell line and exposed in vitro to gamma-ray or gemcitabine to investigate the relevance of REG4 to the resistance to chemotherapy or radiotherapy. In 23 patients with resectable pancreatic cancer, the serum concentration of REG4 was measured before preoperative chemoradiotherapy, and the histologic response was evaluated after the surgery.', 'A 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and fluorescence activated cell scanning (FACS) revealed that REG4-overexpressing cells were resistant to gamma-radiation but showed a modest resistance to gemcitabine. The patients with a higher REG4 level, but not carcinoembryonic antigen or CA-19-9, showed an unfavorable histologic response to chemoradiotherapy (Spearman, rho = 0.439, P = 0.039). The patients showing a higher REG4 level experienced local recurrence postoperatively.
Example Output:
Is serum REG4 level a predictive biomarker for the response to preoperative chemoradiotherapy in patients with pancreatic cancer?