CD70 is a rapidly internalising cell surface antigen that shows a minimal expression on normal tissue but is frequently upregulated on haematologic malignancies (Al Saati et al, 1989; Lens et al, 1999; McEarchern et al, 2007), nasopharygeal carcinomas (Agathanggelou et al, 1995), and renal cell carcinomas (Junker et al, 2005; Diegmann et al, 2006; Law et al, 2006). Here, CD70 is linked to renal cell carcinoma.