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.

[Q]: Context: Biliary tract cancers (BTCs) are uncommon and are associated with a dismal prognosis. Combinations of gemcitabine and platinum chemotherapy (gemcitabine and platinum-based therapy [GP]) form the standard approach for treating advanced BTC. To characterize the spectrum of mutations and to identify potential biomarkers for a GP response in BTC, this study evaluated the genomic landscape and assessed whether mutations affecting DNA repair were associated with GP resistance.', 'Pretreatment, formalin-fixed, paraffin-embedded samples from 183 BTC patients treated with GP were analyzed. Cox regression models were used to determine the association between mutations, progression-free survival (PFS), and overall survival (OS).', 'When genes with an incidence>10% were considered, no individual gene was independently predictive of a GP response. In patients with unresectable BTC who received GP as their first-line therapy, the joint status of cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein 53 (TP53), and AT-rich interaction domain 1A (ARID1A) was associated with PFS (P=.0004) and OS (P.0001). Patients with mutations in CDKN2A and TP53 were identified as a poor-prognosis cohort with a median PFS of 2.63 months and a median OS of 5.22 months. Patients with mutant ARID1A, regardless of the single-mutation status of TP53 or CDKN2A, had similar outcomes. A patient who exhibited mutations in all 3 genes had a median PFS of 20.37 months, and OS was not reached.
Answer: In the largest exploratory analysis of this kind for BTC, 3 prevalent, mutually exclusive mutations represent distinct patient cohorts. These mutations are prognostic and may represent a predictive biomarker for a GP response. Prospective studies to validate these findings are needed, and they should include the incorporation of therapies that exploit the genomic instability observed with these mutations in BTC. Cancer 2016;122:3657-66. ©️ 2016 American Cancer Society.
[A]: Does next-generation sequencing survey of biliary tract cancer reveal the association between tumor somatic variants and chemotherapy resistance?

[Q]: Context: Parkinsonian signs, especially gait impairment, are common and associated with morbidity and mortality in older persons. Our objective was to test the hypothesis that substantia nigra neurofibrillary tangles (NFTs) are related to parkinsonian signs in older persons with and without dementia.', "We studied 86 deceased older Catholic clergy without idiopathic Parkinson's disease from the Religious Order Study, a longitudinal clinical-pathological study. Mean age at death was 85.3 years. Signs of gait disturbance, bradykinesia, rigidity, and tremor were assessed proximate to death using a modified Unified Parkinson's Disease Rating Scale. Forty-micrometer paraffin-embedded sections of substantia nigra were bleached before tau immunohistochemistry and the optical disector was used to count NFTs. We used multivariable linear regression to examine parkinsonian signs as a function of nigra NFTs, controlling for age, sex, education, and cortical NFTs.", 'Substantia nigra NFTs were present in 67 of 86 persons (77.9%). After controlling for age, sex, education, and cortical NFTs, nigra NFTs were related to gait impairment (p < 0.001), but not bradykinesia, rigidity, or tremor. Results were not confounded by dementia, Braak score, neuroleptic medication, cerebral infarcts, or Lewy bodies.
Answer: NFTs in the substantia nigra are associated with gait impairment in older persons with and without dementia.
[A]: Are substantia nigra tangles related to gait impairment in older persons?

[Q]: Context: To identify factors that influence peri-operative hemorrhage in view of reducing the need for transfusions in patients undergoing trans uretheral resection of prostate (TURP).', 'All patients undergoing TURP between January 1997 and December 1999 were identified using ICD 9CM coding and indexing system. Overall 430 patients were identified, however, 384 charts were included and reviewed for demographics, pre and intra-operative data and post-operative morbidity. Patients were divided into two groups on the basis of presence of significant hemorrhage.', 'Overall 384 patients were analyzed. Nineteen patients had hemorrhage--group I whereas 365 had no significant hemorrhage--group II. Mean age and co-morbidities in the two groups were similar. However, in group I, 58% presented with urinary retention compared to 33% in group II. In group I, factors that reached statistical significance include; operative time (p<0.05), mean resected tissue weight (p<0.02), and patient presentation (urinary retention) (p<0.032). There was no significant difference in the two groups with respect to type of anesthesia (regional versus general) and histology of the resected tissue. Patients with mean pre-operative hemoglobin of 10.6 % had a 37% transfusion rate.
Answer: Operative time, weight of resected prostate tissue are inter related and are only partly controllable. Low pre-operative hemoglobin is the only reversible factor in reducing transfusion following TURP.
[A]:
Does optimization of low pre-operative hemoglobin reduce transfusion requirement in patients undergoing transurethral resection of prostate?