Are early infectious exposures involved in the etiology of childhood CNS tumors?

Evaluation of: Schmidt LS, Kamper-Jorgensen M, Schmeigelow K et al. Infectious exposure in the first years of life and risk of central nervous system tumours in children: analysis of birth order, childcare attendance and seasonality of birth. Br. J. Cancer 102(11), 1670-1675 (2010). Early infectious exposures have been implicated in the etiology of childhood CNS tumors. The article evaluated here assesses whether infectious exposure in the first years of life is involved by analyzing birth order, childcare attendance and seasonality of birth. The conclusion is that exposure to infectious disease in early childhood does not play an important role in the etiology of pediatric CNS tumors. It is noted that the measures used are only proxies for infectious exposures and, as such, may not accurately reflect the underlying infectious burden. Furthermore, this study is from the Nordic countries and from a later period than previous studies. Differences in patterns of exposure to infection may vary geographically between countries and may have changed over time. However, the authors have not excluded the possibility that a specific infectious agent is involved, and it is agreed here that future efforts should include a focus on a search for such an agent or agents, as well as formulating plausible, diagnostic-specific, mechanistic hypotheses.