Overexpression of bone morphogenic protein (BMP)-4 mRNA in gastric cancer cell lines of poorly differentiated type.

Gastric cancer is classified as the poorly differentiated and the well differentiated type, depending on its histological, biological, and genetic characteristics. Bone metastasis is more frequently detected in the poorly differentiated type than in the well differentiated type. The prognosis of patients with diffuse osteoplastic bone metastasis of gastric cancer is extremely poor. In this study, we examined the mRNA expression of bone morphogenic proteins (BMPs) in seven gastric cancer cell lines: OKAJIMA, TMK1, MKN45, and KATO-III derived from the poorly differentiated type; and MKN7, MKN28, and MKN74, derived from the well differentiated type. BMP-2 was expressed only in TMK1. BMP-4 mRNA was over-expressed in OKAJIMA, MKN45 and KATO-III, weakly expressed in MKN7, MKN28, and MKN74, but was not expressed in TMK1. Although the biological roles of BMP-2 and BMP-4 expression in gastric cancer remain to be elucidated, these results indicate that BMP-4 mRNA is preferentially overexpressed in the poorly differentiated type of gastric cancer.