Re: Francesco Piva, Matteo Santoni, Marina Scarpelli, et al's Letter to the Editor re: Daniel M. Geynisman. Anti-programmed Cell Death Protein 1 (PD-1) Antibody Nivolumab Leads to a Dramatic and Rapid Response in Papillary Renal Cell Carcinoma with Sarcomatoid and Rhabdoid Features. Eur Urol 2015;68:912–4