Smoking causes lung cancer, at least a dozen other cancers, as well as cardiovascular disease and lung disease.

CNN: Is secondhand smoke really that risky?

Secondhand smoke also causes lung cancer, heart and lung disease in non-smokers.

CNN: Is secondhand smoke really that risky?

But what is more curious is this: the retrovirus is closely related to a free-living virus called Jaagsiekte sheep retrovirus, which causes lung cancer in sheep and goats, but not other species.

ECONOMIST: A virus has been subverted into helping its host

"The results show clearly that second-hand smoke causes cancer of the lung, mouth and throat, " a BMA spokesman said.

BBC: NEWS | Health | Cancer alert for smoking parents

The more prevalent causes of death for male and female smokers were lung cancer and other respiratory diseases followed by heart disease, stroke, and vascular disease.

FORBES: The Smoking Gun: Women Catch Up To Men On Lung Cancer Risk

There are others, but if we look at the one that is most pervasive and causes the largest number of disease in this country, lung cancer is rising and it's rising because we have not been able to get this cancer-causing agent off the street.

CNN: Debaters Agree Cancer War Should Stress Prevention

The study commissioned by NHS Kidney Care says it causes up to 45, 000 premature deaths each year, more than lung and breast cancer combined.

BBC: Kidney care 'needs to improve'

Lung cancer is a different disease than is breast cancer, with different risk factors and different causes.

NPR: Confronting Misconceptions About Cancer Prevention