It started with a brief but poignant comment from China's first lady Peng Liyuan, and it has led to an American psychologist and smoking-cessation researcher and a Chinese scientist working together to solve one of China's biggest problems: helping 316 million smokers quit.

When she accompanied her husband President Xi Jinping on a trip to Seattle last September, Peng visited the Fred Hutchinson Cancer Research Center. She met with center president and director Gary Gilliland, philanthropist Bill Gates and others.

The visit's purpose was for Peng to learn more about collaborative efforts between the center and China.

During her visit to the cancer center's campus, Peng was briefed by Jonathan Bricker, head of the Tobacco and Health Behavior Science Research Group at the center. He spoke about his research using a clinically proven smoking-cessation app for US smartphones. Studies show that using the app is two to three times is more effective than trying to quit cold turkey.

Peng has led a campaign to lower smoking rates in China, where an estimated 1 million die each year of tobacco-related causes, according to the World Health Organization. In 2012, she and Gates appeared together to promote an anti-smoking campaign in Beijing, ahead of the 25th World No-Tobacco Day.

After Bricker told Peng that a similar app could help 16 million people a year in China quit, Peng said, "In my own family there are three smokers. I really hope they can find a better way to quit smoking."

At the time, no one expected the impact of that remark.

But Cheng Feng, a professor and chief physician at the Research Center for Public Health and School of Medicine of Tsinghua University, read the media coverage of the conversation and was very interested in Bricker's work.