PROM1 and nonpapillary renal cell carcinoma: While pSTAT3Ty705 is known to translocate to and act in the nucleus as a transcription factor, pSTAT3Ser727 exerts biological effects in mitochondria.16, 18, 19, 20 Since ligation of TNFR2 increases the expression of TNFR2 and pSTAT3Ser727, we wondered if these proteins are expressed and associated with mitochondria in ccRCC‐CD133+CSCs.