PROM1 and nonpapillary renal cell carcinoma: Quantification of the percentage of TUNEL+CD133+cells from normal kidney (NK‐CD133+cells) and clear cell renal carcinoma (ccRCC‐CD133+CSCs) following treatment with wtTNF, R1TNF or R2TNF alone for 30 min/37°C or with siRNA targeting TNFR2 or STAT3 or negative controls (UT and NTsiRNA) for 72 h/37°C (±wtTNF) and (±z‐VAD‐fmk and/or necrostatin‐1) for 1 h/37°C prior to treatment