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Background: There is a relationship between malaria in the United States and brain tumor incidence, seen in data on malaria outbreaks in 2004 from the Centers for Disease Control and Prevention and reports of brain tumor incidence by state from 19 US states. Methods: In the present study, data from 50 US states and the District of Columbia on malaria outbreaks in 1994, compiled by the Centers for Disease Control and Prevention, was analyzed in relation to state by state all cancer mortality data, 1950-94, from the National Cancer Institute. Results: There was a significant association of malaria incidence with all cancer mortality in 50 US states and the District of Columbia. The association was independent of state population size, percentage black population by state, and median population age. Conclusion: The association between malaria and cancer mortality can be possibly explained by the well established ability of Plasmodium to induce suppression of the immune system. A second explanation may be that the anopheles mosquito, the vector of malaria, transmits an obscure virus that initially causes only a mild transitory illness but much later predisposes to cancer.