GRPR and neoplasm: To examine the GRP-R mAb-1 inhibitory function on GRP/GRP-R downstream signaling and neuroblastoma tumor cell growth, we pretreated BE(2)-C/shCON and shGRP-R cells with GRP-R mAb-1 (1 μg/ml) one hour prior to bombesin (a GRP analog) treatment.