Anti-STF1 antibodies enable researchers to detect and measure the STF1 antigen in biological samples. This target is a reported synonym of the CSTA gene, which encodes cystatin A. This protein is known to function in cell adhesion and keratinocyte differentiation, among other biological roles. The human version of STF1 has a canonical amino acid length of 98 residues and a protein mass of 11 kilodaltons. It is reported to be localized in the cytoplasm of cells and notably expressed in many tissues, such as the appendix and endometrium. STF1 is a member of the Cystatin protein family.