In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
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Question: Context: The cyclooxygenase-2 (cox-2) pathway is now recognized to be important in human cancer development and progression. The gene for cox-2 carries a common single nucleotide polymorphism, T8473C, located within a potential functional region in the 3'-UTR of cox-2 gene was identified. We have investigated the frequencies of cox-2 genotypes in Tunisian population to determine whether that polymorphism was associated with the risk of nasopharyngeal carcinoma (NPC) in Tunisian population.", 'One hundred and eighty-nine NPC patients were compared to 237 healthy controls.', 'The cox-2 T8473C polymorphism was significantly associated with NPC (P=0.031). The CC-genotype and C allele were more frequent in control compared to patients group [CC: OR=0.37; P=0.013; 95% CI: 0.17-0.81; C: OR=0.72; P=0.032; 95% CI: 0.53-0.97]. Multivariate logistic regression analyses revealed that the CC-genotype was associated with a significantly decreased risk of NPC (P=0.013). Tumor sizes, histologic grade, presence of primary lymph node metastases, age or sex were not associated with cox-2 genotypes.\Question: Does the CC-genotype of the cyclooxygenase-2 gene associate with decreased risk of nasopharyngeal carcinoma in a Tunisian population?

Answer: We conclude that the CC-genotype and C allele of cox-2 T8473C gene polymorphism are associated with decreased risk of nasopharyngeal carcinoma in a Tunisian population.

Question: Context: Symptomatic patients with severe aortic stenosis (AS) demonstrate abnormal left ventricular (LV) mechanics. The aim of this study was to compare mechanics in asymptomatic and symptomatic patients with severe AS using two-dimensional myocardial strain imaging.', 'One hundred fifty-four patients with severe AS (aortic valve area 1.0 cm(2)) referred to a heart valve clinic from 2004 to 2011 were studied. Thirty patients were asymptomatic, with normal LV ejection fractions ( 55%), without other significant valvular disease or wall motion abnormalities. Thirty-two symptomatic patients who underwent early aortic valve replacement, with similar age, gender, LV ejection fraction, and aortic valve area, were selected for comparison. Both groups were also compared with 32 healthy subjects with similar age and gender distributions and normal echocardiographic results who served as controls. LV longitudinal and circumferential strain and rotation were measured using speckle-tracking software applied to archived echocardiographic studies. Conventional echocardiographic and myocardial mechanical parameters were compared among the study subgroups.', 'Patients with asymptomatic severe AS demonstrated smaller reductions in longitudinal strain, higher (supernormal) apical circumferential strain (-38 6% vs -35 4%, P < .05), and extreme (supernormal) apical rotation (12.2 4.9 vs 2.9 1.7, P < .0005) compared with symptomatic patients. Apical rotation < 6 was the single significant predictor of symptoms in logistic regression analysis of clinical, echocardiographic, and mechanical parameters. Twelve asymptomatic patients underwent eventual aortic valve replacement and showed decreases in strain and apical rotation compared with baseline values.\Question: Are symptoms in severe aortic stenosis associated with decreased compensatory circumferential myocardial mechanics?

Answer: Longitudinal strain was uniformly low in patients with severe AS and lower in those with symptoms. Compensatory circumferential myocardial mechanics (increased apical circumferential strain and rotation) were absent in symptomatic patients. Thus, myocardial mechanics may help in the follow-up of patients with severe AS and timing of valve surgery.

Question: Context: Yes-associated protein (YAP), a downstream target of the Hippo signaling pathway, was recently linked to hepatocarcinogenesis in a mouse hepatocellular carcinoma (HCC) model. The objective of the current study was to investigate the clinical significance of YAP in HCC and its prognostic values in predicting survival and tumor recurrence.', 'The authors collected 177 pairs of tumor and adjacent nontumor tissue from HCC patients with definitive clinicopathologic and follow-up data. YAP expression was determined by immunohistochemistry, Western blot analysis, and quantitative polymerase chain reaction. Association of YAP with each clinicopathologic feature was analyzed by Pearson chi-square test, and HCC-specific disease-free survival and overall survival by Kaplan-Meier curves and log-rank test. Multivariate Cox regression analyses of YAP in HCC were also performed.', 'YAP was expressed in the majority of HCC cases (approximately 62%) and mainly accumulated in the tumor nucleus. Overexpression of YAP in HCC was significantly associated with poorer tumor differentiation (Edmonson grade; P = .021) and high serum alpha-fetoprotein (AFP) level (P < .001). Kaplan-Meier and Cox regression data indicated that YAP was an independent predictor for HCC-specific disease-free survival (hazards ratio [HR], 1.653; 95% confidence interval [95% CI], 1.081-2.528 [P = .02]) and overall survival (HR, 2.148; 95% CI, 1.255-3.677 [P = .005]).\Question: Is yes-associated protein an independent prognostic marker in hepatocellular carcinoma?

Answer:
YAP is an independent prognostic marker for overall survival and disease-free survival times of HCC patients and clinicopathologically associated with tumor differentiation and serum AFP level. It is a potential therapeutic target for this aggressive malignancy.