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.

Example Input: Context: Current staging for renal cancer (RC) does not directly rely on tumor size. We examined the increment in accuracy related to inclusion of pathologically determined tumor size in prediction of nodal metastases (N+), distant metastases (M+), and cancer-specific survival (CSS).', 'Partial or radical nephrectomy was performed in 2245 patients with clear cell histology. Pathologic stages were T1a in 566, T1b in 490, T2 in 303, T3 in 831, and T4 in 55 patients. Tumor size was 0.5-25 cm (mean, 6.8). Multivariate models relied on 1997 and 2002 TNM variables and addressed N+, M+ disease, and CCS. Their accuracy was compared according to either the presence or absence of tumor size.', 'In all univariate and multivariate models, tumor size was a statistically significant predictor of all outcomes (p< or =0.001). In all multivariate models, tumor size added between 3.7% and 0.8% to predictive accuracy of either 1997 or 2002 TNM categories.
Answer: Tumor size represents a highly significant, multivariate, and informative predictor of RC outcomes and may warrant inclusion in future TNM revisions.
Example Output: Does tumor size improve the accuracy of TNM predictions in patients with renal cancer?

Example Input: Context: Intestinal ischemia/reperfusion (I/R) injury is believed to be the major initiator of the systemic inflammatory response syndrome. As a result of intestinal I/R, the gut becomes a major source of inflammatory cytokine production. We have previously shown that heparin-binding EGF-like growth factor (HB-EGF) is cytoprotective after intestinal I/R and down-regulates pro-inflammatory cytokine production in vitro. We now examine the effects of HB-EGF on pro-inflammatory cytokine expression in vivo.', 'Rats were randomized into three groups: sham-operated, superior mesenteric artery occlusion (SMAO) for 90 min followed by 8 h of reperfusion (I/R), and I/R with intraluminal administration of HB-EGF 25 min after the initiation of ischemia (I/R + HB-EGF). Serum was drawn at 2, 4, 6, and 8 h post reperfusion for determination of cytokine protein levels using a bioplex suspension array system. Additional animals underwent the same ischemic protocol followed by 30 and 60 min of reperfusion with harvesting of ileal mucosa. Ileal pro-inflammatory cytokine gene expression was determined using reverse transcriptase polymerase chain reaction (RT-PCR) with primers specific for TNF-alpha, IL-6, and IL-1beta.', 'HB-EGF decreased TNF-alpha, IL-6, and IL-1beta serum protein levels at 4, 6, and 8 h after intestinal I/R injury. In addition, HB-EGF decreased local intestinal mucosal mRNA expression of TNF-alpha, IL-6, and IL-1beta 30 and 60 min after intestinal injury.
Answer: We conclude that pro-inflammatory cytokine expression is increased both locally and in the systemic circulation after intestinal I/R and that the administration of HB-EGF significantly reduces intestinal I/R-induced pro-inflammatory cytokine expression in vivo.
Example Output: Does heparin-binding EGF-like growth factor decrease inflammatory cytokine expression after intestinal ischemia/reperfusion injury?

Example Input: Context: Human xenografts in athymic mice are frequently used as preclinical models of cancer to investigate the targeting of drugs. In order to distinguish specific from nonspecific targeting of the xenograft, the mice can be implanted with different malignant cell lines. We studied in xenograft success and growth rates after implantation of human lymphoma and breast cancer cells to begin an assessment of the validity of this approach for distinguishing specific from nonspecific targeting. Investigations were undertaken to determine the effect of two different cell-line xenografts, and prior radiation needed for one of the xenografts, on implantation success and growth rates.', 'Female athymic mice were given 4 Gy of external beam radiation 4 days prior to subcutaneous (s.c.) abdominal implantation of 6 x 10(6) Raji human lymphoma cells. One week later, 3 x 10(6) hamster blood transfusion (HBT) 3477 human breast cancer cells were implanted s.c. in a contralateral abdominal site. Xenografts were evaluated frequently thereafter. Xenograft success and growth rates were compared to those observed in "historical" control groups, wherein only a single xenograft of each type was implanted.', 'Raji xenografts developed from 73.7% of the implantations, and 100% of the HBT 3477 xenografts were successful in the experimental group. The "historical" Raji xenograft success rate was 74.1% (+/-9.3%), and the "historical" HBT 3477 xenografts success rate was 99.0% (+/-1.1%). HBT 3477 xenografts did not affect the growth rate of the Raji xenografts, and the mean doubling time for the experimental Raji xenografts was 6.3 days (+/-4.5 days), compared to the "historical" control group mean of 5.1 days (+/-3.9 days; p = 0.2). Similarly, the growth rates for the HBT 3477 xenografts were not affected by the Raji xenografts and the pre-radiation needed for this model. Mean doubling time for HBT 3477 xenografts in the presence of Raji xenografts was 9.2 days (+/-17.6 days), compared to a doubling time of 1.4 days (+/-15.2 days; p = 0.55 and 0.94 studies 1 and 2, respectively). Mean HBT 3477 xenograft doubling time for the "historical" control group was 4.4 days (+/-6.0 days).
Answer: Implantation of Raji xenografts and HBT 3477 breast cancer xenografts in the same mouse did not affect xenograft success or growth rates, even when whole-body radiation of 4 Gy was used to promote Raji xenografts. These observations are not intended to imply an absence of differences in other biological parameters in this sytem or to encourage extrapolation of the conclusions indiscriminately to other preclinical models. Contrarily, our aim was to encourage other investigators to further validate these frequently used approaches.
Example Output:
Does implantation of different malignant human cell lines in an athymic mouse alter success and growth rates of either xenograft?