Bone morphogenetic protein-7 expression reflects the high proliferative ability and aggressiveness of thymic epithelial tumors

Abstract

Background: Bone morphogenetic protein-7 (BMP-7) is a transforming growth factor-β superfamily member. We examined whether BMP-7 expression in thymic epithelial tumors is associated with their clinicopathological features. Methods: One hundred and thirty-two clinical specimens were analyzed in this study. The expression of BMP-7 was detected using immunohistochemistry and was scored as 0, 1, 2, or 3 according to its intensity and was then classified as negative (score 0 and 1) or positive (2 and 3). In addition, Ki-67 staining was performed in type B3 thymoma and thymic cancer. Results: The positive ratio of BMP-7 was 80% in thymic cancer and 70% in thymoma type B3. In contrast, the positive ratios of BMP-7 in type B2 (29.1%), B1 (3.7%), AB (26%), and A (31%) were relatively low. The mean Ki-67 labeling index of the BMP-7 positive group (10.1%±5.9%) was significantly higher than that of the BMP-7 negative group (4.9%±5.9%) in type B3 thymoma and thymic cancer (P=0.012). The BMP-7 positive group showed significantly poorer overall survival (OS) than the BMP-7 negative group across all patients with thymic epithelial tumors and in all types of thymomas (P=0.006, P=0.018); however, no difference was observed in thymic cancers. Conclusions: This study showed that high expression of BMP-7 correlated with a poor prognosis in patients with thymic epithelial tumors, and the expression of BMP-7 was higher in type B3 thymomas and thymic cancers than in other types of thymomas. BMP-7 might serve as a novel prognostic biomarker for thymic epithelial tumors.

Promotor methylation status of MAPK4 is a novel epigenetic biomarker for prognosis of recurrence in patients with thymic epithelial tumors

“…In contrast, the Masaoka staging system divides TETs into four stages based on invasiveness 6 . However, many biological behaviors of TETs remain unclear 7 . Thus, the current WHO classification and Masaoka staging system cannot reflect these undefined biological behaviors of TETs, limiting them as prognostic factors for TETs.…”

“… 6 However, many biological behaviors of TETs remain unclear. 7 Thus, the current WHO classification and Masaoka staging system cannot reflect these undefined biological behaviors of TETs, limiting them as prognostic factors for TETs. For example, even with complete resection, some TET patients still experience metastatic or local recurrence, which renders significant obstacles to the long‐term survival of TET patients.…”