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.

Ex Input:
Context: Invasive species can have devastating effects on native ecosystems and therefore impose a significant threat to human welfare. The introduction rate of invasive species has accelerated dramatically in recent times due to human activity (anthropogenic effects), with a steadily growing pool of widespread tramp species. We present an in-depth analysis of four pantropical species of Xyleborus ambrosia beetles (Xyleborus volvulus, Xyleborus perforans, Xyleborus ferrugineus, and Xyleborus affinis) with similar ecology (fungus cultivation in dead wood), reproductive biology (permanent inbreeding) and genetic system (haplodiploidy). The unique combination of reproductive traits and broad host plant usage pre-adapts these beetles for colonizing of new areas.', 'We found that all four species were broadly distributed long before human-assisted dispersal became common, and that the impact of anthropogenic effects varied among the species. For X. volvulus, X. perforans, and X. affinis there was evidence of ancient establishment in numerous regions, but also of abundant recent introductions into previously colonized areas. For X. ferrugineus, we found clear biogeographical structuring of old clades, but little evidence for recent successful introductions.
Answer: Our results indicate that current human-aided transoceanic dispersal has strongly affected the genetic makeup of three of the species in this study. However, current biogeographical patterns of all four species are equally, if not more strongly, influenced by ancient establishment on different continents.

Ex Output:
Do globally distributed Xyleborus species reveal recurrent intercontinental dispersal in a landscape of ancient worldwide distributions?


Ex Input:
Context: Is a perioperative metastatic screening programme indicated in patients presenting with primary operable breast cancer and no signs of distant metastases?', 'The impact of staging results (chest X-ray, bone scanning, liver ultrasound) for prognosis, treatment, quality of life and costs was retrospectively analysed in 1 076 patients with an operable breast cancer and no clinical signs of metastases.', 'Staging examinations revealed 30 (2.8 %) distant metastases, 130 (12.1 %) suspect findings and excluded metastases in 916 (85.1 %) patients. Further diagnostic procedures confirmed distant metastases in 7 (5.4 %) and excluded them in 123 (94.6 %) out of 130 patients with suspect findings. Distant metastases were detected more frequently with increasing tumor size (pT < or = 2.0 cm: 1.6 %, pT 2.1-5.0 cm: 3.0 %, respectively pT > 5.0 cm: 15.1 %; p < 0.001) and increasing number of involved axillary lymph nodes (pN0: 1.4 %, pN1-3 +: 1.8 %, pN4-9 +: 4.0 %, pN > 10 +: 12.5 %; p < 0.001). Due to false positive findings 123 (11.4 %) patients had to live for a significant period of time with the psychological distress of suspected metastatic disease. The abandonment of a perioperative screening in 1 076 patients saves costs of at least euro 259,366.68.
Answer: In breast cancer patients without clinical signs of tumor spread perioperative screening for metastases is not warranted because of low frequency of metastases, false positive findings, missing therapeutic consequences and high costs.

Ex Output:
Is [ A perioperative screening for metastatic disease indicated in patients with primary breast cancer and no clinical signs of tumor spread ]?


Ex Input:
Context: To assess whether differential expression of caspase-3 in paired metastatic lymph nodes (LNs) is prognostic of survival in patients with resectable esophageal squamous cell carcinoma (ESCC).', 'Capases-3 expression was evaluated immunohistochemically in 122 pairs of primary ESCCs and regional metastatic LNs assembled on tissue microarrays. The impact of caspase-3 expression on survival outcomes was analyzed by the Kaplan-Meier method and Cox proportional hazards regression model.', 'The level of caspase-3 expression was significantly higher in LN metastases than in primary tumors (P < 0.001). Caspase-3 expression in the primary tumors was associated with longer median survival (23 mo vs 21 mo, P = 0.033), whereas higher expression in paired metastatic LNs was associated with shorter median survival (20 mo vs 22 mo, P = 0.043). Multivariate analysis showed that both were independent prognostic factors.
Answer: Caspase-3 expression in metastatic LNs may be a potential independent predictor of poorer overall survival in patients with resected ESCC and LN metastasis. Protein expression in metastatic tumors may be a biomarker prognostic of survival.

Ex Output:

Is caspase-3 expression in metastatic lymph nodes of esophageal squamous cell carcinoma prognostic of survival?