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 Q]: Context: Women diagnosed with pregnancy-associated breast cancer postpartum have a worse prognosis, stage for stage, than other women with breast cancer. The time of breast involution is tumor promotional. The extracellular matrix protein tenascin-C is upregulated during involution in animal models and promotes breast cancer progression. It interacts with transforming growth factor (TGF)β, which also is involved in breast involution and breast cancer progression. Little is known about the expression of tenascin-C during human breast involution, nor its relationship to TGFβ. The purpose of this study was to investigate the expression of tenascin-C throughout lactation, as well as its relationship to TGFβ1 and TGFβ2.', 'Three milk samples from 25 lactating women (transitional, whole, and wean) were collected, separated into components (cells, fat, and skim), and the skim fraction analyzed for total protein, tenascin-C, TGFβ1, and TGFβ2. Tenascin-C, TGFβ1, and TGFβ2 were detectable in all milk samples.', 'Highest tenascin-C levels on average were found in whole milk, whereas highest mean TGFβ1 and TGFβ2 levels were in wean milk. Wean samples on average had higher levels of both TGFβ1 (26%) and TGFβ2 (>500%) than matched transitional milk samples. Tenascin-C levels in wean milk were associated with nursing length (p = 0.048). Combining all three milk collection time points, tenascin-C exhibited a weak inverse correlation with TGFβ1 and TGFβ2 (p < 0.1). The inverse correlation at the wean time point was stronger for TGFβ2 than -1 (-0.37 versus -0.25). Tenascin-C, a protein known to promote breast cancer progression, is expressed throughout lactation.
Answer: The inverse correlation with TGFβ2 in wean milk suggests a possible interaction during breast involution, which should be further investigated.
[EX A]: Does expression of the Extracellular Matrix Protein Tenascin-C vary During Lactation?

[EX Q]: Context: Although the presence of perineural invasion has been recognized as a poor prognostic factor in extrahepatic cholangiocarcinoma, the molecular mechanisms of perineural invasion in extrahepatic cholangiocarcinoma remain unclear. Nerve growth factor has been reported to be a candidate predictive biomarker of perineural invasion in some cancers.', 'To investigate the impact of intratumoral nerve growth factor expression in resected extrahepatic cholangiocarcinoma on survival.', 'Intratumoral nerve growth factor expression was investigated immunohistochemically in 112 patients with resected extrahepatic cholangiocarcinoma. Associations between nerve growth factor expression and clinicopathological factors were statistically evaluated, and risk factors for poor survival were analyzed using univariate and multivariate analyses.', 'High and low nerve growth factor expression was observed in 62 (55%) and 50 (45%) patients, respectively. For all 112 patients, no significant correlation was found between nerve growth factor expression and presence of perineural invasion (P = 0.942). Moreover, nerve growth factor expression was not associated with recurrence-free survival (P = 0.861) and overall survival (P = 0.973). In multivariate analysis, lymph node metastasis (P = 0.004) was identified as an independent risk factor for early recurrence and the presence of perineural invasion (P = 0.002) and lymph node metastasis (P < 0.001) was identified as independent risk factors for poor survival.
Answer: Intratumoral nerve growth factor expression is not associated with perineural invasion or recurrence-free and overall survival in patients with resected extrahepatic cholangiocarcinoma.
[EX A]: Is nerve Growth Factor Expression Associated with Perineural Invasion in Extrahepatic Cholangiocarcinoma?

[EX Q]: Context: To assess the activity and tolerability of temozolomide in children with progressive low-grade gliomas (LGGs).', "The authors reviewed the records of 13 children (6 months to 19 years old) with progressive LGGs and magnetic resonance imaging evidence of unresectable tumors who were treated with temozolomide at the authors' institution since 1999.", 'Four patients received a 5-day regimen of temozolomide (150 mg/m2 per day) repeated every 28 days, and nine patients received a 42-day regimen (75 mg/m2 per day) repeated every 56 days. Three patients demonstrated partial responses to temozolomide, with a median time to maximal response of 5 months (range 4-12 months), and one had a minor response at 9 months. Four patients developed progression while on temozolomide, with a median time to progression of 7 months (range 1-12 months). Five patients had disease stabilization. Among the five patients with prior chemotherapy and/or radiation therapy, temozolomide was associated with disease stabilization in three and tumor response in one. In the three patients with neurofibromatosis type 1, two patients experienced tumor responses and one disease stabilization. Thrombocytopenia, nausea, emesis, and fatigue were the most common toxicities. Four patients discontinued therapy because of the side effects.
Answer: Temozolomide is active in children with LGGs. It is effective in previously treated patients and in patients with neurofibromatosis type 1. The 42-day regimen appears less toxic than the 5-day regimen. Any impact on survival for these patients remains to be demonstrated.
[EX A]:
Is temozolomide active in childhood , progressive , unresectable , low-grade gliomas?