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: Thyroid cancer is the most common endocrine gland malignancy. Advances in understanding the genetic basis for thyroid cancer revealed the potential involvement of several genes in the formation of thyroid tumors. Mutations in the gene coding for succinate dehydrogenase subtype B (SDHB) have been implicated in papillary thyroid cancer (PTC). Succinate dehydrogenase (SDH) is a heterotetrameric protein composed of four subunits, SDHA, SDHB, SDHC, and SDHD, and participates in both the electron transport chain and the tricarboxylic acid cycle. The aim of the study was to evaluate the association between variants in the SDHA, SDHB, SDHC, and SDHD genes and familiar PTC in a large Brazilian family.', 'Four patients with PTC, 1 patient with PTC and gastrointestinal stromal tumor (GIST), 1 patient with GIST, and their relatives - several of them with different thyroid problems - from a large Brazilian family were screened for genetic variations of SDHx genes with the use of polymerase chain reaction-single-stranded conformational polymorphism and direct sequencing.', 'Only one rare variation in SDHA was found in some of the family members, but not segregating with the disease. No other genetic variants of these genes were detected in the family members that presented with PTC and/or GIST.\Question: Is familiar Papillary Thyroid Carcinoma in a Large Brazilian Family Associated with Succinate Dehydrogenase Defects?

A: Familiar PTC and a GIST were not associated with SDHx mutations; additional genetic defects, yet unknown, may be responsible for the development of tumor.
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Q: Context: Ascent to high altitude leads to a reduction in ambient pressure and a subsequent fall in available oxygen. The resulting hypoxia can lead to elevated pulmonary artery (PA) pressure, capillary stress, and an increase in interstitial fluid. This fluid can be assessed on lung ultrasound (LUS) by the presence of B-lines. We undertook a chamber and field study to assess the impact of high-intensity exercise in hypoxia on the development of pulmonary interstitial edema in healthy lowlanders.', 'Thirteen volunteers completed a high-intensity intermittent exercise (HIIE) test at sea level, in acute normobaric hypoxia (12% O2, approximately 4090 m equivalent altitude), and in hypobaric hypoxia during a field study at 4090 m after 6 days of acclimatization. Pulmonary interstitial edema was assessed by the evaluation of LUS B-lines.', 'After HIIE, no increase in B-lines was seen in normoxia, and a small increase was seen in acute normobaric hypoxia (2 2; P < .05). During the field study at 4090 m, 12 participants (92%) demonstrated 7 4 B-lines at rest, which increased to 17 5 immediately after the exercise test (P < .001). An increase was evident in all participants. There was a reciprocal fall in peripheral arterial oxygen saturations (Spo2) after exercise from 88% 4% to 80% 8% (P < .01). B-lines and Spo2 in all participants returned to baseline levels within 4 hours.\Question: Does high-intensity intermittent exercise increase pulmonary interstitial edema at altitude but not at simulated altitude?

A: HIIE led to an increase in B-lines at altitude after subacute exposure but not during acute exposure at equivalent simulated altitude. This may indicate pulmonary interstitial edema.
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Q: Context: The assessment of microsatellite instability (MSI) is not included yet in the routine evaluation of patients with gastric cancer, as controversial data exist regarding its prognostic value.', 'We determined the clinical significance of MSI in 510 sporadic gastric cancers, using the mononucleotide markers BAT25 and BAT26. The results were compared with the immunohistochemical expression of the mismatch repair proteins Mlh1 and Msh2.', 'MSI was present in 83 (16%) cancers and correlated with better survival (P < .001). Multivariate analysis showed that the MSI phenotype was an independent factor (P = .005) and added prognostic information to TNM stage, location, and age. The relative risk of death for MSI cancer patients was 0.6 (95% confidence interval [CI], 0.4-0.8). Moreover, when grouped according to stage, only stage II cancers showed a significant effect of MSI status on survival (P = .011; hazard ratio = 0.3; 95% CI, 0.1-0.8). MSI also correlated with older age (P = .002), female gender (P < .001), intestinal histotype (P = .011), lower T stage (P = .018), and less lymph node involvement (P < .001). Finally, comparison of the results of immunohistochemical expression of the mismatch repair proteins Mlh1 and Msh2 with microsatellite analysis showed concordant results in 95% of neoplasms, with a sensitivity of 82% and specificity of 98%.\Question: Is microsatellite instability in gastric cancer associated with better prognosis in only stage II cancers?

A:
Microsatellite analysis of gastric cancer has clinical utility in determination of prognosis, but should be determined in only stage II neoplasms in a routine clinical setting. Immunohistochemistry may be considered sufficient, although microsatellite analysis is preferable.
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