TNFRSF12A and kidney disorder: A soluble form of Fn14 (sFn14) was detected in serum and urine of a mouse model of the kidney disease nephrotoxic nephritis and in serum of healthy humans, but it remained unclear whether this sFn14 comprises only the ectodomain and, thus, results from proteolytic ectodomain shedding or represents full‐length Fn14, potentially released from multivesicular bodies or dead cells (Sharif et al, 2016; Chen et al, 2018, 2019).