The present invention features methods for treating, stabilizing, preventing, and/or delaying cancer by administering nanoparticles that comprise rapamycin or a derivative thereof. The invention also provides compositions (e.g., unit dosage forms) comprising nanoparticles that comprise a carrier protein and rapamycin or a derivative thereof. The invention further provides combination therapy methods of treating cancer comprising administering to an individual an effective amount of nanoparticles that comprise rapamycin or a derivative thereof and a second therapy.