In a study conducted by Mayer et al. (2005), UA showed antiproliferative activity against MCF-7 breast cancer cells (estrogen receptor-positive, wild type for p53) and MDA MB 231 (estrogen receptor-negative, non-functional p53) with an IC50 of 18.9 and 22.3 μM, respectively [53]. The gene discussed is TP53; the disease is breast cancer.