Rapamycin inhibits tumor growth in vivo. a. Rapamycin inhibits tumor growth in KMH2 (Hodgkin-lymphoma) xenografts in vivo. Tumor volumes are shown in control and rapamycin-treated mice during an 8-week treatment. Tumor weight at the end of the experiment is also indicated; tumors in rapamune treated mice were significantly smaller (p<0.05). b. Confirmation of the in vivo anti-proliferative and apoptotic effect of rapamycin by IHC detection of pHH3 (proliferation marker) and cleaved/activated caspase3 (apoptosis marker) (*:p<0.05, **:p<0.01).