CD38 and plasma cell myeloma: Additionally, CD38 is expressed at relatively low levels on normal lymphoid and myeloid cells, making it an attractive candidate for use in myeloma treatment (Lin, Owens, Tricot, & Wilson, 2004; Santonocito et al., 2004; Kim, Park, Medeiros, & Weissman, 2012; Hosen, 2013).