A new report by the World Health Organization says cancer will overtake heart disease as the world's top killer by 2010. The development is part of a trend that likely will more than double global cancer cases and deaths by 2030. The WHO said in its report that rising tobacco use in developing countries such as China and India — where 40% of the world's smokers live — is believed to be a key reason for the shift.

The WHO estimates as many as 75 million people worldwide could be living with cancer by 2030.