Endogenous Fn14 was detected in the lysate of the human breast cancer cell line MDA‐MB‐231 and the human ovarian cancer cell line SKOV‐3 with an apparent molecular weight of about 14 kDa (Fig 3A–D), which is lower than for the transfected Fn14 constructs because of the lack of the epitope tags. Here, TNFRSF12A is linked to breast carcinoma.