Novel orthotopic uterine leiomyosarcoma model demonstrated enhanced tumor growth, metastasis, and chemosensitivity compared to subcutaneous counterparts.

Researchers asked whether an orthotopic mouse model, in which SK-LMS-1-derived uterine leiomyosarcoma xenografts are surgically implanted into the uterine myometrium, could better reproduce human uLMS than traditional subcutaneous models that rarely metastasize. Compared with subcutaneous tumors, orthotopic tumors grew faster by co-opting host uterine vasculature, showed less hypoxia and more proliferation, and spontaneously metastasized in 37% of mice by four weeks. They also responded more strongly to doxorubicin (55% versus 44% volume reduction), suggesting the model is a more physiologically relevant platform for studying uLMS and testing therapies.