Abstract 1160: Inactivated hippo-pathway as a prognostic biomarker in hepatocellular carcinoma.

Abstract

Abstract The contact inhibition of proliferation and cell movement is crucially important in embryonic development, tissue regeneration, and wound healing for the well-controlled organogenesis. The disruption of contact inhibition results in sustained cell proliferation and uncontrolled cell movement, which is a hallmark of solid tumors. Loss of contact inhibition allows cancer cells to facilitate the invasion of neighboring tissues and metastasis to remote organs. The recently identified Hippo signaling pathway has been implicated in contact inhibition of proliferation as well as organ size control. Indeed, the conditional inactivation of hippo-pathway in liver leads to enlarged liver (massive hepatomegaly) and tumorigenesis (Cell, 2007). Clinically, HCC often shows the huge tumor more than size in 10cm, strongly speculating that inactivation of hippo-pathway plays an important role in HCC progression. However, clinical significance of hippo-pathway in HCC is largely unknown. Here, we investigated the clinical significance of inactivated hippo-pathway, which induce overexpressed oncogenes (YAP/TAZ), using resected 80 HCC samples, and suggested the tumoral-high TAZmRNA expression was a worse prognostic biomarker for HCC patients represented by high proliferative activity. The tumor size in High TAZmRNA expression group (n =24) was significantly larger than that in low expression group (n = 56) (P < 0.05). YAP/TAZ protein over-expression in HCC was associated with high proliferative activity by Ki-67 positive cells. The high TAZmRNA expression group showed significantly worsen disease free survival and overall survival compared with that in low expression group (P = 0.01 and 0.02, respectively). Thus, inactivation of Hippo-pathway plays a crucial role in tumor progression by accelerating proliferative activity, and tumoral TAZmRNA expression level may be a useful prognostic biomarker in HCC. Citation Format: Hiromitsu Hayashi, Hideyuki Kuroki, Naomi Yokoyama, Shigeki Nakagawa, Hidetoshi Nitta, Katsunori Imai, Daisuke Hashimoto, Yoshiaki Ikuta, Akira Chikamoto, Toru Beppu, Hideo Baba. Inactivated hippo-pathway as a prognostic biomarker in hepatocellular carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1160. doi:10.1158/1538-7445.AM2013-1160