However, a non-significantly increased risk of mTOR inhibitor associated FAEs is observed in sub-group analysis according to the mTOR inhibitors, tumor types and controlled therapy, for which we suggest several possible explanations: the small number of events recorded; under-reporting of rare (<5%) adverse events; the fact that clinical trials are usually not designed specifically to address toxic events; and the small number of randomized controlled trials included. The gene discussed is MTOR; the disease is neoplasm.