Reply to Isabel Heidegger, Renate Pichler, and Andreas Pircher's Letter to the Editor re: Erik Bovinder Ylitalo, Elin Thysell, Emma Jernberg, et al. Subgroups of Castration-resistant Prostate Cancer Bone Metastases Defined Through an Inverse Relationship Between Androgen Receptor Activity and Immune Response. Eur Urol 2017;71:776–87