简介：Maleandfemalesexhormonesareessentialforprenatalandpostnatalsexualdevelopment,andformanyaspectsofadultreproductivehealth.However,evidencefromexperimentalanimalstudiesandclinicalepidemiologicaldataindicatesthatprolongedexposuretoendogenoussexsteroidspromotesneoplastictransformationintheglandularepitheliaofsecondarysexualorgans(e.g.breast,uterus,prostate).Sexsteroidsrecruitmitoticallyquiescent(Go)cellstoentertheproliferativecellcycle(G1andSphases)byincreasingtheexpressionofregulator).proteins,evclinsandcyclin-dependentkinases.Sexsteroidsalsorepressgenesthatactivateapoptoticprogvammedcelldeath.Thesemitogenicandantiapoptotieactionscanincreasethelikelihoodofrandomgeneticerrorsandpromotethedevelopmentandprogressionofcancers.Forclinicians,themostimportantaspectofthisrelationshipisthemodestincreasedriskofbreastandprostaticmalignancies,overbackgroundrates,attributabletotheuseofexogenoussexsteroidsforcontraceptionandhonnonereplacementtherapy(HRT).Tiffscontributionfocnsesonthisaspect.