CEACAM5 and cancer: MPPs are synthesized with specific biological components, including antibodies or aptamers, in order to target cancer markers or cancer cells, such as carcinoembryonic antigens [101], circulating tumor cells [102], circulating tumor DNAs [ref], RNA extract from cancer cells [81], breast-cancer cells, floating leukemia cells [57], and Bronchioalveolar stem cells [103].