ERBB2 and prostate cancer: These include tissues specific antigens, i.e., antigens found principally in one type of tumor cells, e.g., melanoma cells, prostate cancer cells, pancreatic tumor cells etc. A second group of is antigens is shared by a variety of tumors such as certain oncogenes (e.g., p53 NY-ESO1, MUC.1, and Her2-neu).