Although xenograft co-culture with MDA-MB-231WT or oxygen and glucose levels did not affect MDA-MB-231EP300KD growth in vivo or in vitro, respectively, it is conceivable that the complex interplay between cancer cells, in particular CSC and the tumor environment may affect growth and tip the balance towards the suppression of tumor outgrowth after EP300 knockdown. The gene discussed is EP300; the disease is neoplasm.