While both receptors are often co-expressed in tumor cell lines, and albeit loss of TRAIL-R1 can be found in many tumor cell lines, occurrence of a TRAIL-R2-deficiency in TRAIL-R1 expressing cells is rare, and has to our knowledge only been described in the human erythroleukemia cell line Hel [22]. The gene discussed is TNFRSF10B; the disease is neoplasm.