GNRH2 and breast cancer: To analyze the effects of GnRH-II antagonist treatment on apoptotic signaling in GnRH-I receptor-negative (GnRH-I receptor knockdown) human breast cancer cells in comparison to the GnRH-I receptor-positive (wild-type) human breast cancer cells, we measured the GnRH-II antagonist-induced activation of stress activated MAPK p38 (Figure 2a) in GnRH-I receptor-negative (GnRH-I receptor knockdown) MCF-7 and MDA-MB-231 human breast cancer cells (Figure 2a).