Meg O’Brien is an infectious disease epidemiologist who has worked with health ministries and health care providers to expand access to affordable, high-quality treatment for HIV and cancer. As vice president for global cancer treatment at the American Cancer Society, O’Brien has established innovative partnerships to get treatment to more patients around the world through Allied Against Cancer, an alliance of organizations working together to improve access to cancer care in low- and middle-income countries, with a focus on sub-Saharan Africa.