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: Human breast tumors are heterogeneous and consist of phenotypically diverse cells. Breast cancer cells with a CD44+/CD24- phenotype have been suggested to have tumor-initiating properties with stem cell-like and invasive features, although it is unclear whether their presence within a tumor has clinical implications. There is also a large heterogeneity between tumors, illustrated by reproducible stratification into various subtypes based on gene expression profiles or histopathological features. We have explored the prevalence of cells with different CD44/CD24 phenotypes within breast cancer subtypes.', 'Double-staining immunohistochemistry was used to quantify CD44 and CD24 expression in 240 human breast tumors for which information on other tumor markers and clinical characteristics was available. Gene expression data were also accessible for a cohort of the material.', 'A considerable heterogeneity in CD44 and CD24 expression was seen both between and within tumors. A complete lack of both proteins was evident in 35% of the tumors, while 13% contained cells of more than one of the CD44+/CD24-, CD44-/CD24+ and CD44+/CD24+ phenotypes. CD44+/CD24- cells were detected in 31% of the tumors, ranging in proportion from only a few to close to 100% of tumor cells. The CD44+/CD24- phenotype was most common in the basal-like subgroup--characterized as negative for the estrogen and progesterone receptors as well as for HER2, and as positive for cytokeratin 5/14 and/or epidermal growth factor receptor, and particularly common in BRCA1 hereditary tumors, of which 94% contained CD44+/CD24- cells. The CD44+/CD24- phenotype was surprisingly scarce in HER2+ tumors, which had a predominantly CD24+ status. A CD44+/CD24- gene expression signature was generated, which included CD44 and alpha6-integrin (CD49f) among the top-ranked overexpressed genes.\Question: Does the CD44+/CD24- phenotype is enriched in basal-like breast tumors?

Answer: We demonstrate an association between basal-like and particularly BRCA1 hereditary breast cancer and the presence of CD44+/CD24- cells. Not all basal-like tumors and very few HER2+ tumors, however, contain CD44+/CD24- cells, emphasizing that a putative tumorigenic ability may not be confined to cells of this phenotype and that other breast cancer stem cell markers remain to be identified.


Question: Context: Endotoxin, when delivered shortly before or during mechanical ventilation, increases susceptibility to ventilation-associated lung injury. However, it is unclear whether increased susceptibility to ventilator-associated lung injury is still present after clinical recovery from a transient endotoxin challenge.', 'Anesthetized rats were submitted to a 4-h period of mechanical ventilation with low (8 ml/kg) or high (24, 27, or 30 ml/kg) tidal volumes (VTs) 24 h after transient illness had been provoked by a single nonlethal intravenous injection of Escherichia coli endotoxin. Control animals were injected with phosphate-buffered saline and underwent the same protocol.', 'At 24 h, endotoxin-treated nonventilated animals showed no symptoms of clinical illness, and oxygenation was comparable with that of controls, but lung neutrophil counts were increased. Compared with controls, mechanical ventilation with high VT induced a stronger pulmonary inflammatory response and more severe lung injury in endotoxin-treated animals, as indicated by impaired oxygenation, increased lung wet-to-dry weight ratio, and increased levels of protein, neutrophils, and cytokines in lung lavage fluid. In addition, the highest VT resulted in increased mortality in endotoxin-treated animals. Low VT after endotoxin treatment did not cause functional pulmonary impairment but induced an inflammatory response.\Question: Does increased susceptibility to ventilator-associated lung injury persist after clinical recovery from experimental endotoxemia?

Answer: In this animal model, a 24-h delay after a single systemic injection of endotoxin resulted in clinical recovery and preserved pulmonary function but did not prevent increased susceptibility to ventilator-associated lung injury provoked by high VT. Residual pulmonary inflammation and neutrophilic infiltration at initiation of mechanical ventilation probably contribute to these findings.


Question: Context: Operative management of patients with persistent N2 disease after induction therapy is still debated.', 'One hundred fifty-three consecutive patients underwent pneumonectomy from January 1999 until July 2005; 28 patients (18.3%) had persistent N2 disease after induction therapy (group 1), 32 patients (20.9%) had pathologic stage N0 or N1 after induction therapy (group 2), and 93 patients (60.8%) with pathologic N2 disease underwent immediate surgery (group 3). Short-term end points were operative mortality at 30 and 90 days and major complications. Long-term end points were 5-year survival and disease-free survival rates.', 'Demographics of the three groups were similar (age, sex, side of operation, type of chemotherapy, smoking status, and comorbidity such as coronary artery disease, diabetes, and chronic obstructive pulmonary disease). Thirty-day postoperative mortality was 10.7% in group 1, 3.1% in group 2 (p = 0.257), and 4.3% in group 3 (p = 0.201); 90-day postoperative mortality was 10.7% in group 1, 12.5% in group 2 (p = 0.577), and 9.7% in group 3 (p = 0.558). Incidence of major postoperative complications was similar. Five-year survival rate was 32.2% (median, 28 months; 95% confidence interval, 7 to 43) in group 1, 34.8% (median, 27 months; 95% confidence interval, 7 to 47) in group 2 (p = 0.685), and 12.4% (median, 15 months; 95% confidence interval, 11 to 19) in group 3 (p = 0.127). No statistical difference was found in terms of 5-year event-free survival, or regarding the side of pneumonectomy.\Question: Does persistent N2 disease after induction therapy jeopardize early and medium term outcomes of pneumonectomy?

Answer:
Our results suggest that pneumonectomy is justified in patients with persistent N2 disease after induction chemotherapy.