Researchers at the Veterans Affairs Medical Center in Shreveport, Louisiana examined the records of 297 patients diagnosed with kidney cancer from 1987 to 2009.
Canola, whose seeds are pressed to make the popular cooking oil, is a type of oilseed rape developed by breeders in Canada. In the US, it is grown mainly in North Dakota and Minnesota through cultivation, is spreading.
Transgenic crops are engineered with specialized trait like herbicide resistance. For years, scientists have known that transgenic crops can pass on their traits to nearby weeds through hybridization.