Once the presence of EpCAM positive CTCs in the blood of patients was confirmed using two methodologies, an expression profile analysis, including a panel of genes related to cell plasticity and ovarian cancer aggressiveness (MUC1, CK19, CXCR4, TIMP1, ALDH1, CD24, CD44, GDF1), was carried out. The gene discussed is ALDH1A1; the disease is ovarian carcinoma.