BMP4 and cancer: 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.