Q: 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.
Context: To investigate the clinical significance of Oct-4 in the development and progression of gastric cancer.', 'Immunohistochemistry was used to analyze Oct-4 expression in 412 gastric cancer cases. Oct-4 protein levels were upregulated in gastric cancer tissues compared with adjacent noncancerous tissues.', 'Positive expression of Oct-4 correlated with age, depth of invasion, Lauren classification, lymph node metastasis, distant metastasis, and TNM stage. In stages I, II, and III, the 5-year survival rate of patients with high expression of Oct-4 was significantly lower than that in patients with low expression of Oct-4. In stage IV, Oct-4 expression did not correlate with the 5-year survival rate. Furthermore, multivariate analysis suggested that the depth of invasion, lymph node metastasis, distant metastasis, TNM stage, and upregulation of Oct-4 were independent prognostic factors of gastric cancer.
Answer: Oct-4 protein is a useful marker in predicting tumor progression and prognosis.
A:
Is oct-4 associated with gastric cancer progression and prognosis?