The primary objectives of Ludwig Cancer Research are to prevent and control cancer through basic and translational research. Lloyd Old, the organization’s former director and scientific chairman, participated in the discovery of Tumor Necrosis Factor (TNF) and the tumor suppressor p53. He contributed to the immunosurveillance hypothesis, from which modern cancer immunotherapy can be derived. Thierry Boon, former director of the organization’s Brussels branch, made foundational contributions to the field of cancer immunotherapy. The prevailing model of carcinogenesis in the late 1970s held that spontaneously arising tumors were unlikely to elicit immune responses. Boon and his team, who believed otherwise, were the first to isolate genes that code for a family of tumor antigens and show that T cells could recognize and target cancer cells bearing such antigens. This theory is being tested in a number of current clinical trials. Ludwig researchers in Melbourne discovered and cloned the granulocyte-monocyte colony stimulating factor (GM-CSF) through a collaboration with Australian immunologist Donald Metcalf. The factor is essential to the maturation of key white blood cells, and has been used extensively over the past few decades to help rebuild the immune system of patients undergoing chemotherapy. It is also being tested as a therapeutic agent in combination with several experimental immunotherapies for cancer. The Oncology Drug Advisory Committee of the US FDA recently recommended approval for T-VEC, a viral therapy for melanoma manufactured by Amgen that incorporates the gene for GM-CSF to support anti-cancer immune responses. Ludwig researchers in Sao Paulo played a role in establishing that human papillomavirus (HPV) infection causes cervical cancer. They ran the largest epidemiological studies of HPV infection and reported that chronic, though not transient, infection by the virus dramatically increases the risk of cervical cancer, laying the groundwork for the clinical development of an HPV vaccine. Current and former Ludwig researchers contributed to an emerging class of cancer immunotherapies known as checkpoint inhibitors. They explored the underlying immunology of the response and played a role in evaluating the first such drug in clinical trials for the treatment of advanced melanoma. This led the development of new criteria for evaluating responses of cancer patients to immunotherapy in clinical trials. Contributions to the field of cell signaling include the identification of signaling pathways and subsequent development of therapies. An example is the PI3K family of proteins, which play a key role in cell signaling that fuels cancer.