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.

[Q]: Context: Oxidative stress plays an important role in Alzheimer's disease (AD) etiopathogenesis. There were several studies that showed impaired antioxidant defense system (ADS) enzymes expression or activity in AD patients. There are only few studies evaluating the importance of ADS gene single nucleotide polymorphisms (SNPs) as risk factors of AD. We evaluated association between chosen SNPs of the enzymes of the ADS and risk of AD.", 'We included 400 AD patients and 402 healthy controls. We studied rs1041740, rs4998557 and rs2070424 of the SOD1 gene, rs2855116, rs5746136 and rs4880 of the SOD2 gene and rs3448, rs1050450 and rs1800668 of the GPx-1 gene (real time PCR). To determine the APOE gene common polymorphism, two single-nucleotide polymorphisms (SNPs; NCBI SNPs rs429358 and rs7412) were genotyped (TaqMan assays, Applied Biosystems [ABI], Foster City, CA, USA). The genotype and gender frequencies were compared between the studied groups by the χ(2) test and mean age by the t-Student test.', 'Among all studied SNPs only rs2070424 of the SOD1 gene was a protective factor for AD in an additive (OR=0.47; 95% CI=0.30-0.74, p=0.001) and recessive (OR=0.47; 95% CI=0.30-0.75, p=0.002) models including age, gender and APOE gene status.\Question: Is rs2070424 of the SOD1 gene associated with risk of Alzheimer 's disease?
[A]: rs2070424 polymorphism of the SOD1 gene is a risk factor for AD in Polish population. Allel G and genotype AG and GG are protective factors for AD.


[Q]: Context: Although successful cochlear implantation of patients with deafness following meningitis is expected, long-term stability of electrical current requirements has not been systematically evaluated. This study evaluated changes in programming for patients deafened by bacterial meningitis and stability of auditory performance over time.', 'In this retrospective descriptive study, cochlear implant (CI) stimulation mode and performance of 14 patients deafened by meningitis were compared with those of an age-matched control group of patients deafened by other causes.', 'There were no significant differences in mean performance between the meningitis group and control group (P > 0.05). However, the postmeningitis group required progressively higher stimulation levels and higher programming modes over time as compared to the control group.\Question: Do changes in programming over time in postmeningitis cochlear implant users?
[A]: Even with deafness accompanied by labyrinthine ossification attributed to meningitis, neural elements were present and could be stimulated. Because increasing levels of stimulation were required over time, postmeningitic children with CIs, and those with cochlear ossification in particular, may need frequent programming adjustments to maintain performance.


[Q]: Context: Pancreatic neuroendocrine tumors (PNETs) are a group of rare tumors. Chromogranin A (CgA) was considered as the most practical and useful serum tumor marker in PNET patients. But peripheral blood levels of CgA are not routinely tested in Chinese patients with PNETs. This study was to assess the diagnostic value of CgA in Chinese patients with PNETs especially in patients with insulinomas.', 'Eighty-nine patients with PNETs including 57 insulinomas and 32 non-insulinoma PNETs as well as 86 healthy participants were enrolled in this study between September 2003 and June 2013. Serum levels of CgA were measured by ELISA method. Expression of CgA protein was detected in 26 PNET tissues including 14 insulinomas by immunohistochemical staining.', 'Serum levels of CgA in 89 PNET patients were significantly higher than that in healthy controls (P\u2009=\u20097.2\u2009×\u200910-9). Serum levels of CgA in 57 patients with insulinomas (median 64.8\xa0ng/ml, range 25-164) were slightly higher than the levels in healthy controls (median 53.4\xa0ng/ml, range 39-94) but much lower than the levels in 32 patients with non-insulinoma PNETs (median 193\xa0ng/ml, range 27-9021), P\u2009=\u20090.001. The serum CgA levels were reduced in 16 of 17 patients with insulinomas after tumor resection. ROC curve showed that CgA values at 60\xa0ng/ml distinguished patients with insulinomas from healthy controls but its sensitivity and specificity were 66.7% and 73.3%, respectively. In contrast, CgA values at 74\xa0ng/ml distinguished patients with non-insulinoma PNETs from healthy controls, and the sensitivity and specificity were 65.6% and 91.9%, respectively. Except for two insulinomas with negative staining of CgA, 12 insulinoma tissues showed positive staining of CgA.\Question: Is chromogranin A a reliable serum diagnostic biomarker for pancreatic neuroendocrine tumors but not for insulinomas?
[A]:
CgA is a reliable serum diagnostic biomarker for PNETs but not for insulinomas.