The human B-cell precursor leukemia cell line BLaER1 was derived from the transfection of the Burkitt Lymphoma Cell Line Seraphina, an acute lymphoblastic leukemia (ALL) cell line with the CCAAT/enhancer-binding-protein (C/EBPα), the estrogen receptor (ER) coupled to green fluorescent protein (GFP) (Gaidt et al., 2018). Here, ESR1 is linked to Burkitt lymphoma.