Activationofthephosphoinositide3kinase(PI3K)/Akt/mammaliantargetofrapamycin(mTOR)pathwayiscommoninbreastcancer.Thereispreclinicaldatatosupportinhibitionofthepathway,andphaseⅠtoⅢtrialsinvolvinginhibitorsofthepathwayhavebeenorarebeingconductedinsolidtumorsandbreastcancer.Everolimus,anmTORinhibitor,iscurrentlyapprovedforthetreatmentofhormonereceptor(HR)-positive,humanepidermalgrowthfactorreceptor2(HER2)-negativebreastcancer.Inthisreview,wesummarisetheefficacyandtoxicityfindingsfromtherandomisedclinicaltrials,withsimplifiedguidelinesonthemanagementofpotentialadverseeffects.Educationofhealthcareprofessionalsandpatientsiscriticalforsafetyandcompliance.WhilethereissomeclinicalevidenceofactivityofmTORinhibitioninHR-positiveandHER2-positivebreastcancers,thebenefitsmaybemorepronouncedinselectedsubsetsratherthanintheoverallpopulation.FurtherdevelopmentofpredictivebiomarkerswillbeusefulintheselectionofpatientswhowillbenefitfrominhibitionofthePI3K/Akt/mTOR(PAM)pathway.
