AR and metastatic prostate carcinoma: Ectopic expression of Wnt5a in prostate cancer cells attenuated the antiproliferative effects of AR inhibition, whereas its suppression in drug-resistant cells restored partial sensitivity to anti-AR treatment.46 Altogether, these studies provide evidence that CTC analysis in patients with metastatic prostate cancer is an opportunity to reveal those key mechanisms of resistance to AR inhibitors, as well as to identify those patients who would benefit the most from a targeted treatment.