Figure 4.

Fibroblasts expressing Twist1 promote invasion and migration of gastric cancer cells and are negatively associated with patient survival. CCD986sk and IMR90 cell lines infected with lentiviral vectors containing the Twist1 gene reveal that both cell lines expressed Twist1 after infection, and Twist1 was not expressed in control gene (GFP) infected cell lines (A). Using conditioned medium from Twist1-infected fibroblasts and control gene infected fibroblasts, Twist1-expressing skin fibroblasts (B) and lung fibroblasts (C) showed an increased number of invading gastric cancer cells (arrows) in the invasion assay. Twist1-expressing skin fibroblasts (D) and lung fibroblasts (E) showed an increased number of migrating gastric cancer cells (arrows) in the migration assay. Kaplan-Meier survival curves demonstrate that the Twist1 expression in stromal fibroblasts was significantly associated with poor overall survival (F). When all cases were stratified by Lauren classification, Twist1 expression in stromal fibroblasts was associated with poor prognosis in the diffuse-type (G), but not in the intestinal-type (H), gastric carcinoma. Kaplan-Meier estimates of overall survival for 195 patients with gastric cancer from the combined data sets according to the expression patterns of Twist1 in stromal fibroblasts and cancer cells. Overall survival rates were worst in the group showing Twist1 positivity in both fibroblasts and carcinoma cells (I). Lymph node metastasis occurred most frequently in the group showing Twist1 positivity in both fibroblasts and carcinoma cells, followed by the group that was Twist1 positive in fibroblasts but negative in carcinoma cells (P < 0.001 for trend) (J).