To have an effective cancer vaccine, it is important to identify molecules on tumor cells that the human immune system can see as foreign (tumor antigens). Once found, these tumor antigens can then be used in vaccine preparations to induce a strong immune response that will specifically destroy tumor cells that express this molecule and not normal cells. Dr. Vlad has developed an ovarian cancer vaccine based on the MUC1 tumor antigen, which is expressed at low levels in normal epithelial cells and overexpressed in ovarian cancer. The chemical backbone of MUC1is identical in normal and tumor MUC1, but the cancer form carries tumor-specific carbohydrates. Dr. Vlad proposes to test a vaccine based on the tumor-like, glycosylated MUC1, called Tn100mer. The vaccine delivers small pieces of the tumor form of MUC1 to specialized immune cells, called dendritic cells, which will then activate other cells of the immune system (like T and B cells) to seek out and destroy MUC1-expressing cancer cells. Results from the study of tumor-specific immunotherapy through vaccination with the MUC1 tumor antigen, especially in the context of minimal residual disease following removal of the tumor, could potentially be crucial for prevention of recurrences.