Acknowledgments
We are grateful to P. Karran and M. Sekiguchi for helpful advice. We also thank Y. Yamada, Y. Abe and K. Muta for their expert comments. The expert assistance in DNA extraction, DNA sequencing and immunohistochemistry by Y. Ogata, M. Hanaki, S. Kato and Y. Kubota is also gratefully acknowledged.
Potential conflict of interest
Disclosure forms provided by the authors are available with the full text of this article online at https://dx.doi.org/10.1080/10428194.2018.1427862.