In his Editorial, “Perceived threats and real killers” (14 May, p. [927][1]), R. I. Glass makes important distinctions between the health impact and scientific effort devoted to common and often controllable infectious agents such as influenza and rotaviruses and rare and unpredictable agents such as Ebola virus. Similar comparisons between perceived threats, real killers, and scientific emphasis could be made with human cancers. Although the threat of developing common cancers such as breast or prostate cancer is real and not perceived, the cancer that is most proficient at killing humans is lung cancer and the etiologic agent is tobacco. Tobacco is responsible for ∼30% of all cancer deaths ([1][2]), and deaths from lung cancer in the United States exceed those of breast cancer, colorectal cancer, and prostate cancer combined ([2][3]). Yet the amount of dollars spent per cancer death by funding agencies has historically favored breast and prostate cancers over lung cancer (sixfold less spent per lung cancer death than per prostate cancer death and ninefold less per lung cancer death than per breast cancer death for National Cancer Institute funding in 2001). The disparity between funding and mortality is consistent with a low level of commitment from the scientific community to study lung cancer: The number of investigators studying rare cancers such as those derived from bone marrow exceeds the number studying the biology of tobacco and lung carcinogenesis. State governments also appear not to perceive tobacco-related illnesses as a real threat because many have opted to use hundreds of millions of dollars in tobacco settlement money to balance skewed budgets and not to address tobacco addiction that fuels these illnesses. Important health issues such as diarrhea, influenza, and lung cancer may not be sexy, but they deserve the public's attention and commitment from policymakers and the scientific community. 1. 1.[↵][4]1. J. Mackay, 2. M. Eriksen , The Tobacco Atlas (World Health Organization, Geneva, Switzerland, 2002). 2. 2.[↵][5]1. A. Jemal 2. et al. , CA Cancer J. Clin. 54, 8 (2004). [1]: /lookup/doi/10.1126/science.304.5673.927 [2]: #ref-1 [3]: #ref-2 [4]: #xref-ref-1-1 View reference 1. in text [5]: #xref-ref-2-1 View reference 2. in text