BCR and neoplasm: Although Samsn1 was shown to have an anti‐proliferative effect in normal B cells following BCR stimulation,29, 31 Samsn1 expression in 5TGM1 cells was previously found to cause only a modest reduction in proliferation and then only when the tumor cells were co‐cultured with bone marrow stromal cells (BMSCs) in vitro.37