Methods
Search strategy
A comprehensive search was conducted for available articles published in
English using the databases of PubMed and Web of Knowledge up to February
2014. The following search terms were used: glioma or cancer or brain cancer AND
red meat (unprocessed) or cured meat or processed meat or diet or lifestyle or food.
We also searched for relevant papers in the reference list of reviews, commentaries,
or original papers through the string N-nitroso brain cancer hypothesis
[13–15] by hand search.