ABSTRACT
The possibility that aspartame had neuro-oncogenic potential was one of the major issues at the Public Board of Inquiry evaluating the safety of aspartame. Brain tumors in various rat strains have been recorded by commercial breeding companies, individual investigators, and governmental agencies. However, many surveys of naturally occurring brain tumors in rats were either carried out in animals that were too young, or were restricted to grossly visible tumors. All tumors observed in the Searle-Hazelton studies were mostly microtumors at the time of necropsy, and only incidentally detected by histological examination. In the two lifetime aspartame feeding studies conducted by Searle-Hazelton, the number of brain tumors was well within the range of reported brain tumor incidences in rats, particularly since the incidence rate was established by microscopic examination of eight sections from every brain. There was no shift in the type of tumor from that normally seen in rats.
