CXCR4 and prostate cancer: As the first study to elucidate the molecular mechanisms underlying ERK1/2 activation by OR51E2, we focus on three important signaling molecules: Gβγ, PI3Kγ and ARF1, which we have recently demonstrated to control CXCR4-mediated ERK1/2 activation in prostate cancer cells (Khater et al., 2021a; Khater et al., 2021b).