 A homologous protein, which can be rendered ineffective by the antibody to pure chicken riboflavin carrier protein, has been shown to occur in several mammalian species, including two species of monkeys, and also in humans.Very recent studies have suggested that circulating RCP levels and the immunohistochemical staining of RCP in biopsy specimens may provide new markers for "breast cancer diagnosis and prognosis".Termination of pregnancy has been demonstrated by immuno-neutralization of RCP in monkeys.