RBP1 and monoclonal gammopathy: For example, hypermethylation in TP53, cyclin-dependent kinase 4 inhibitor B (CDKN2B), glutathione peroxidase 3 (GPX3), retinol binding protein 1 (RBP1), secreted protein acidic and cysteine rich (SPARC), and transforming growth factor beta induced (TGFBI) was shown to be associated with the transition from the pre-leukemic phase monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (Hodge et al., 2005; Kaiser et al., 2013).