TheraPten is a Canadian biotech company developing PTEN-L, the world’s first natural human anti-cancer tumor suppressor protein, as an injectable biological therapy. Tumor suppressors are the body’s prime defense against cancer. However, they become deactivated or eliminated during cancer progression. Moreover, as tumor suppressors cannot penetrate cancer cells they are practically “undruggable”. In contrast, PTEN-L, a naturally occurring, longer form of PTEN has the tantalizing capability to readily penetrate and kill cancer cells. Loss of PTEN reduces response of cancer patients to immuno-oncology antibodies. Therefore, reintroduction of PTEN-L may have profound impact in cancer care.