TNFRSF10D and familial pancreatic carcinoma: Our finding that TRAIL-R3 and TRAIL-R4 staining in tumor samples is found exclusively in the cytoplasm is in agreement with the previous finding that positive staining for TRAIL-R1 and -R2, but negligible staining for TRAIL-R3 and -R4 could be found on the surface of different pancreatic cancer cell lines by FACS analysis [34].