Melanotransferrin (CD228/MFI2/MELTF) is a cell surface glycosylphosphatidylinositol (GPI)-anchored glycoprotein belonging to the transferrin family of iron-binding proteins. CD228 was originally described as a cancer-testis antigen highly expressed on malignant melanoma cells. Data from The Cancer Genome Atlas (TCGA) indicates widespread expression of CD228 in various types of cancer, with recent descriptions of its potential as a biomarker for invasive colorectal cancer.