VHL and nonpapillary renal cell carcinoma: For the cell lines, two immortalized human renal proximal tubular epithelial cells derived from normal kidney cells (RPTEC and HK2), five non-sarcomatoid ccRCC cell lines (786-O, RCC4, RCC4/VHL, Caki-1 and RC2) and four ccRCC cell lines with sarcomatoid differentiation (RCJ41T1, RCJ41T2, RCJ41M and UOK127) were characterized and analyzed.