To determine if the GSK3-MUC signaling pathway is also impacted by modulation of B2AR and/or MOR receptor activity in vivo, we studied the effects of PRO (10 mg/kg body weight; [29]), NTX (10 mg/kg body weight; [29]), and PRO + NTX on the growth of the tumor and on the expression of genes related to GSK3-MUC1 signaling in MDA-MB-231 cell rat xenografts. Here, MUC1 is linked to neoplasm.