The Kufe laboratory identified the human DF3/MUC1 carcinoma-associated protein in the early 1980s. Estimates indicate that MUC1 is overexpressed in about 900,000 of the 1.4 million tumors diagnosed each year in the United States. Translational research in the Kufe laboratory is focused on the development of approaches that block MUC1-C subunit function with soluble receptors and antibodies against the MUC1-C extracellular domain. The demonstration that MUC1-C transforming function is dependent on the formation of oligomers has also provided the experimental framework for designing agents, such as cell-penetrating peptides and small molecules, that block its oligomerization. Based on this work, the first-in-man MUC1-C inhibitor, designated GO-203, has entered Phase I evaluation in patients with refractory solid tumors.