MAPK3 and breast cancer: To address how DRD5-signalling was related with the decrease of ERK1/2-activation and the attenuation of STAT3-phosphorylation, we determined whether DRD5-stimulation was coupled to cAMP production in DCs, as cAMP has been involved in the attenuation of both ERK1/2 and STAT3 pathways in breast cancer cells (60, 61).