We determine that RP215 recognizes a single band of IgG heavy chain in cancer cell extracts from EpCAM (epithelial cell adhesion molecule)-positive cancer cells isolated from ascitic fluid of ovarian cancer patients, as well as several cancer cell lines, including breast cancer (MDA-MB-231 and MCF-7), prostate cancer (PC3) and lung cancer (A549) (Figure 1A a and 1A b). The gene discussed is EPCAM; the disease is ovarian carcinoma.