Role of the Stemness Factors Sox2, Oct3/4, and Nanog in Gastric Carcinoma

BackgroundCancer stem cells have been proposed to be responsible for cancer tumorigenicity, and then to persist in tumors as a distinct population and cause relapse and metastasis. Recently, the stemness factors Sox2, Oct3/4, and Nanog were associated with induced pluripotent stem cells, suggesting a correlation between these stemness factors and cancer stem cells. We therefore investigated the role of stemness factors in the tumorigenesis of human gastric cancer.Materials and MethodsA total of 290 patients who had undergone resection of a primary gastric cancer at our institute were enrolled. A curative R0 resection was performed for 253 of 290 patients, and the remaining 37 patients were treated with a palliative resection. The expression levels of Sox2, Oct3/4, and Nanog were analyzed by immunohistochemistry.ResultsSox2, Oct3/4, and Nanog expression were positive in 159 (55%), 129 (44%), and 28 (10%) of 290 gastric cancers, respectively. There was a statistically significant correlation between Sox2-positive or Oct3/4-negative expression and invasion depth, lymph node metastasis, or lymphatic invasion. In 253 patients with a curative resection, the prognosis of patients with Sox2-positive tumors or Oct3/4-negative tumors was significantly (P < 0.01 or P = 0.04, log-rank) worse than that of patients with Sox2-negative or Oct3/4-positive tumors, respectively. A multivariate analysis revealed the expression of Sox2 or Oct3/4 to be an independent prognostic factor (P = 0.01 or P = 0.04).ConclusionsSox2-positive expression or Oct3/4-negative expression might be associated with invasion of gastric cancer. Sox2 and Oct3/4 might be independent prognostic factors for patients with gastric cancer.