Peng Liyuan, wife of Chinese president Xi Jinping, (R) speaks with Melinda Gates, as she walks towards a lab for a tour at the Fred Hutchinson Cancer Research Center in Seattle, Washington, Sept 23, 2015. Bill Gates (L), Co-Chair and Trustee of the Bill and Melinda Gates Foundation and Research Center president and director Dr Gary Gilliland (C), follow in a group behind. [Photo/Agencies]