The role of endoglin plays in angiogenesis and the modulation of TGF beta receptor signaling, which mediates cellular localization, cellular migration, cellular morphology, cell proliferation, cluster formation, etc., makes endoglin an important player in tumor growth and metastasis. Being able to target and efficiently reduce or halt neoangiogenesis in tumors would prevent metastasis of primary cancer cells into other areas of the body. Also, it has been suggested that endoglin can be used for tumor imaging and prognosis.
The role of endoglin in cancer can be contradicting at times since it is needed for neoangiogenesis in tumors, which is needed for tumor growth and survival, yet the reduction in expression of endoglin has in many cancers correlated with a negative outcome of that cancer. In breast cancer, for example, the reduction of the full form of endoglin, and the increase of the soluble form of endoglin correlate with metastasis of cancer cells.  The TGF beta receptor-endoglin complex relay contradicting signals from TGF beta as well. TGF beta can act as a tumor suppressor in the premalignant stage of the benign neoplasm by inhibiting its growth and inducing apoptosis.  However, once the cancer cells have gone through the Hallmarks of Cancer and lost inhibitory growth responses, TGF beta mediates cell invasion, angiogenesis (with the help of endoglin), immune system evasion, and their ECM composition, allowing them to become malignant.