Early diagnosis and improvement of breast cancer treatments have reduced breast cancer mortality in recent years, with survival rates reaching 85% today. In spite of these data, breast cancer was still the most frequently diagnosed tumor in the world in 2020, mainly due to increased population screening and social factors such as aging. RANK protein plays a key role in the development of these tumors. Located in the membrane of cells, when it binds to its partner RANKL, it sends signals that stimulate the development of the mammary gland. When these proteins do not work properly, breast cells begin to divide and multiply uncontrollably, resulting in breast cancer.