• mice administered tamoxifen at 2 months of age develop endothelial proliferative lesions from vascular malformations that lead to vascular tumors (angiosarcoma/lymphangiosarcoma); cutaneous tumors in tails and paws and liver tumors develop at 3 months or more after tamoxifen treatment
• cutaneous tumors are also seen on the lips and legs at later time points
• at 3-4 months and 6-8 months after tamoxifen administration, about 30% and 80% of mice develop cutaneous tumors, respectively
• poorly differentiated cutaneous lymphangiosarcomas are highly invasive
• mice treated with rapamycin starting 1 week after tamoxifen administration, do not develop cutaneous or liver tumors
• mice treated with rapamycin after the formation of tumors at 3 months after tamoxifen administration show halted tumor progression and even reduced tumor size and improved survival
• mice treated with axitinib after the formation of tumors at 5 months after tamoxifen show decreased proliferation of tumors, however tumors do not shrink and the number of apoptotic cells remains similar to untreated mice