 This has led to the notion that Dcytb may have an additional role in ascorbate metabolism in scorbutic species.DCYTB protein has also been found in breast tissue (epithelial and myoepithelial cells) and high DCYTB levels are associated with a favourable prognosis in patients with breast cancer.A single nucleotide polymorphism (SNP) within the DCYTB promoter (SNP rs884409) which reduced functional DCYTB promoter activity was also associated with reduced serum ferrtin levels in a patient cohort with C282Y haemochromatosis.