TASK DEFINITION: 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.
PROBLEM: Context: Cytokeratin 19 is significant for indicating cancer cells, and Cyfra 21-1 is a fragment of cytokeratin 19. This retrospective study was designed to define the prognostic value of serum Cyfra 21-1 in epithelial ovarian cancers (EOC).', 'Serum Cyfra 21-1 concentration was obtained from 42 patients with EOC prior to treatment. Various prognostic aspects were examined using univariable and multivariable analyses. The standard serum marker cancer antigen 125 was measured simultaneously and compared in this analysis.', 'Serum levels of both Cyfra 21-1 and cancer antigen 125 were associated with positive retroperitoneal lymph nodes and platinum resistance; higher levels of Cyfra 21-1 (3.0\xa0ng/mL as the cut-off) were associated with shorter disease-free survival (16 months vs. 28 months, p\xa0=\xa00.001) and overall survival (29 months vs. 41 months, p\xa0=\xa00.007) than lower levels. Further univariable analysis showed that Cyfra 21-1, poor differentiation, and retroperitoneal lymph node metastasis were related to platinum resistance and mortality. Multivariable analysis indicated retroperitoneal lymph node metastasis and serum Cyfra 21-1 were independent risk factors for both disease-free survival and overall survival.\Question: Is serum cytokeratin-19 fragment ( Cyfra 21-1 ) a prognostic indicator for epithelial ovarian cancer?

SOLUTION: The pretreatment level of serum Cyfra 21-1 had remarkable prognostic significance for EOC, indicating poor survival when it was elevated above 3.0 ng/mL.

PROBLEM: Context: Poor condition at operation determined by the physiologic POSSUM score is related to postoperative mortality and morbidity of colorectal cancer surgery. This study was designed to analyze the relationship between condition of patients with colorectal cancer at operation and long-term overall survival.', 'A total of 542 patients survived a radical resection for Stages I, II, or III colorectal cancer. Physiologic POSSUM score at surgery, exclusive of age, was calculated for all patients. Mean physiologic POSSUM score was used as cutoff point to determine low-risk and high-risk group patients. A Cox proportional hazard analysis was performed to study the effect of low-risk and high-risk group on overall survival and to identify independent risk factors.', 'Five-year overall survival was significantly higher in low-risk group patients than in high-risk group patients (low-risk group 66.6 percent vs. high-risk group 48.5 percent; P < 0.001). Differences in overall survival also were found when patients in Stages I, II, and III were analyzed separately. Risk factors for overall survival were advanced stage of disease, poor tumor differentiation, mucinous adenocarcinoma, older than age 70 years, and poor condition of the patient at time of operation.\Question: Does pOSSUM predict decreased overall survival in curative resection for colorectal cancer?

SOLUTION: Poor condition at operation, as determined by physiologic POSSUM score, is a risk indicator for long-term overall survival in colorectal cancer patients.

PROBLEM: Context: Hyperhomocysteinemia, increased oxidative stress, and decreased antioxidant defense function have been found to be associated with the risk of chronic kidney disease (CKD). Deficiencies of folate and vitamin B-6 (pyridoxal 5'-phosphate, PLP) may cause hyperhomocysteinemia and increased oxidative stress. The purpose of this study was to determine the associations among homocysteine, folate, PLP, oxidative stress indicator, and antioxidant capacities in patients with stage 2 to 3 CKD, and to further analyze these relationships with respect to risk for CKD.", 'Ninety-seven patients with CKD and 135 healthy subjects were recruited.', 'Patients with CKD had significantly higher levels of malondialdehyde and total antioxidant capacities, but had significantly lower antioxidant enzyme activities compared with healthy subjects. Serum folate but not plasma PLP was significantly negatively associated with plasma homocysteine. There were no significant associations of homocysteine, PLP, and folate with oxidative stress indicator and antioxidant capacities. High homocysteine (odds ratio [OR] = 1.11; 95% confidence interval [CI], 1.02-1.22) and malondialdehyde (OR = 34.24; 95% CI, 4.44-264.40) level increased the risk of CKD, whereas high plasma PLP (OR = 0.98; 95% CI, 0.97-0.99) and superoxide dismutase activity (OR = 0.82; 95% CI, 0.74-0.91) decreased the risk of CKD after adjusting all potential confounders.\Question: Are high homocysteine , low vitamin B-6 , and increased oxidative stress independently associated with the risk of chronic kidney disease?

SOLUTION:
High homocysteine, low PLP, increased oxidative stress, and decreased antioxidant enzyme activity (superoxide dismutase activity) were independent contributing factors in the development of early stage CKD.