CCN1 and plasma cell myeloma: And whereas Johnson et al. showed recombinant CCN1 to inhibit growth of MM cells (Johnson et al. 2014), the viability of primary myeloma cells in the study of Dotterweich et al. increased significantly after CCN1 incubation, implying a pro-myeloma effect of CCN1 (Dotterweich et al. 2014).