**Acknowledgement**

This work was supported in part by grants from Japan China Medical Association to B.Y. This work was also supported in part by grants from the Ministry of Education, Culture, Sports, Science and Technology and by the Promotion and Mutual Aid Corporation for Private Schools of Japan. The authors thank Dr. Chieko Hirobe for encouraging suggestions and arranging sample supply, and Dr. Yamato Kikkawa for providing HCC cell lines for this study.
