TMPRSS6 and prostate cancer: Indeed, similar to TMPRSS6‐3, the catalytically truncated TMPRSS6 mask mutant interacts with HJV13 but does not repress hepcidin promoter activation.40 Moreover, as TMPRSS6 proteolytic activity has been previously described as protective towards prostate cancer in vitro,41 truncated TMPRSS6‐3 or functionally altered TMPRSS6‐4 expression could be related to cancer development and their role in cancers should be thoroughly studied.