Importantly, more than half of the patient‐derived primary cells we tested in vitro were sensitive to BMP4, which implies that BMP4 could have beneficial effects in a large group of patients.7, 9 Multiple myeloma is a very heterogeneous disease, and the malignant cells harbor different genetic aberrations.27 About 50% of all myeloma patients have cancer cells that are hyperdiploid.27 Despite this high number of hyperdiploid cells, very few cell lines have been established with this genotype. Here, BMP4 is linked to plasma cell myeloma.