Periostin on tumor stromal cells might be associated with the malignant progression of patients with gastric cancer

Periostin is one of matrix cellular proteins. It has been reported that the periostin in the tumor microenvironment might regulate the FAK signaling via the interaction with integrins expressed on cancer cells, resulting in the stimulation of proliferation and invasion. In gastric cancer (GC), the periostin has reported to be overexpressed in the tumor stroma, however, the role of periostin and the types of cells remains to be unclear. Then, in this study we examined the significance of periostin on the clinico-pathologic features of GC by immunohistochemical study, using 689 GC samples. Also, 4 GC cell lines were used to examine the effect of periostin on the proliferation and the invasion activity of GC cells by proliferation assay and invasion assay.The immunohistochemical study of periostin confirmed that the expression of periostin was frequently found on stromal fibroblasts in the tumor. High expression of periostin in the tumor stroma is associated with worse survival rates (p < 0.001, log-rank), deeper T invasion (p < 0.001), frequent lymph node metastasis (p < 0.001), distant metastasis (p = 0.021), higher recurrence rates (p < 0.001), and higher stage (p < 0.001). I n vitro assays using GC cell lines demonstrated that periostin significantly promoted the invasion and migration ability of GC cells, but did not affect the proliferation activity.In conclusion, the periostin, which is mainly expressed on the tumor stromal fibroblasts, might be associated with the malignant progression of GC.