Cardiovascular disease and cancer are the leading causes of death in the world.1) Currently in Korea, malignancy is the most common cause of death and heart disease is the second most common cause of death. Because cardiovascular disease and cancer share some risk factors, cancer patients can be considered as a high-risk group of cardiovascular disease, and cardiovascular disease patients also can be a high-risk group for cancer.2)3) Because of the improving survival of cancer patients and the increasing number of cancer survivors, prevention of cardiovascular disease has become an important issue in the management of cancer2)4) As the survival after major cardiovascular diseases, such as acute myocardial infarction (AMI), is getting longer, there is also a need for evidence for cancer prevention in cardiovascular disease, but there is only limited evidence.5)6) In this issue of Korean Circulation Journal, Lee et al.7) provides important data on the effects of smoking on long-term clinical outcomes and lung cancer risk among patients with AMI. Lung cancer and AMI account for the largest proportion of cancer and cardiovascular deaths, respectively. Cigarette smoking is an important modifiable risk factor that contributes greatly to both of the disease.8) However, there is little data on the long-term effects of smoking on morbidity and mortality in patients with AMI. In those who survive AMI, smokers are often observed to have lower or similar mortality rates compared to non-smokers. This is presumed to be due to the fact that AMI patients who smoked had fewer other risk factors than AMI patients who did not smoke, but it is difficult to prove with real world data.