Vogelstein B, Kinzler KW. The multistep nature of cancer. Trends Genet 1993;9:138–41

Extract

Epidemiologic studies (1) have indicated a strong association between tobacco smoking and various human cancers, especially lung cancer. Nearly one third of human cancers are estimated to be related to tobacco use. Direct molecular evidence has been provided in a study (2) demonstrating that carcinogens in tobacco smoke cause a specific type of genetic damage required for cancer development. Fortunately, national anti-cigarettesmoking efforts are expected to reduce the number of teenaged smokers in the next decade and to decrease rates of tobaccorelated cancer mortality. However, the number of marijuana smokers is increasing. A national survey by the Department of Health and Human Services (3) indicated that 1.9% of U.S. high school students smoked marijuana daily in 1992 but that this frequency had increased to 4.6% in 1995. An independent national survey by the Partnership for a Drug-Free America (4) has found that the willingness to experiment with marijuana by children 9–12 years old has risen from 9% in 1993 to 14% in 1997. Marijuana use is becoming a serious social problem in the United States and may become more widespread because of nationwide anti-tobacco campaigns that may have the unintended consequence that teenaged smokers will replace tobacco with marijuana. The prevalence of crack cocaine use among teenagers continues at 8%, and newer easier methods of cocaine consumption continue to be devised (4). Moreover, the public cannot be informed of the potential danger of increased risk for cancer development because of the lack of scientific evidence, yet many known carcinogens exist in marijuana smoke and crack cocaine smoke.