Measles may be a Risk Factor for Malignant Brain Tumors

BACKGROUND A possible risk factor for brain tumor might be measles, since late neurologic sequelae are part of measles pathology. Subacute sclerosing panencephalitis, a devastating neurologic illness, is prone to develop years after measles infection. METHODS Because measles damage to the brain might increase the risk of brain tumor, we examined the relationship of measles incidence in 1960 and brain tumor incidence in 50 US States and the District of Columbia, 2004-2007. Data on number of cases of measles by state in 1960 are from the Morbidity and Mortality Weekly Report. In 1960 measles was a childhood illness. We calculated measles incidence by obtaining the population of each state from the 1960 US Census and then age adjusting our results to the cumulative percent of the state population under age 21, since this would have been the measles-infected group. Data on the percentage white population by state are from the US Census (www.census.gov). Age-adjusted incidence (to the 2000 US standard population) of brain tumors is from the Central Brain Tumor Registry of the United States 2011 report. RESULTS There was a significant correlation between 1960 measles incidence and incidence of malignant brain tumors in persons 20 and older in 2004-2007 (r=0.321, p=0.026). Because glioblastoma is more frequent in whites and males, multivariate linear regression was performed with tumor incidence as the dependent variable, measles incidence, percent white population, and sex ratio by state as independent variables. Measles incidence was significantly correlated with malignant brain tumor incidence (β=0.361, p<0.001) and independent of the effect of race (β=0.734, p<0.001) and sex ratio m/f (β=-0.478, p<0.001). There was no correlation of measles incidence with brain tumor incidence in persons younger than 20. CONCLUSION Inflammation is a critical component of tumor development. The inflammation of measles-induced subacute sclerosing panencephalitis, even subclinical cases, could well promote tumor formation, since many tumors arise from sites of infection, chronic irritation and inflammation.