CD27L is also named for CD70 which is one member of TNF family. CD27L is expressed on T and B lymphocytes and mature DCs. It binds the CD27, which is on the antigen-presenting cells. CD27L is a 19.2 kDa cytokine with 148 amino acid residues which is a transmembrane glycoprotein. CD27L plays an important role in the regulation of T cell proliferation which is also a good target of cancer immunotherapy.