S100A4 and neoplasm: A physical and functional interaction between the metastasis related S100A4 protein and p53 was suggested for the first time by Grigorian et al.[32] and was further investigated in vitro.[33] S100A4 is a member of the vertebrate specific small, (10–20 kDa) EF‐hand containing Ca2+ binding, mostly homodimer protein family[34] that plays pathological roles in tumor metastases and in inflammatory diseases.[35] The Ca2+‐bound active form contains a hydrophobic binding pocket capable of binding to target proteins.