Everything about China is big, including its cancer problem. In some wealthier cities, like Beijing, cancer is now believed to be the most frequent killer. Air pollution, high rates of smoking, and notorious “cancer villages” scarred by industrial pollution are increasing death rates around the country. Liver cancer in particular is four times as prevalent as it is in the West, in part because one in 14 people in China carry hepatitis B, which puts them at risk. Of all the people worldwide who die of cancer each year, some 27 percent are Chinese.