Extracellular GREM1 was detected in the collected conditioned media from control breast cancer cells (MDA-MB-453-shCtrl and SKBR3-shCtrl), while it was undetectable in GREM1-depleted cells (MDA-MB-453-shGREM1 and SKBR3-shGREM1). The gene discussed is GREM1; the disease is breast cancer.