Synucleins are small, soluble proteins expressed primarily in neural tissue and in certain tumors. The family includes three known proteins: α-synuclein, β-synuclein, and γ-synuclein. All synucleins have in common a highly conserved α-helical lipid-binding motif with similarity to the class-A2 lipid-binding domains of the exchangeable apolipoproteins. Although they are homologous, each synuclein is encoded by a different gene on chromosomes 4q21.3-q22. γ-Synuclein (also called BCSG-1) is abnormally expressed in a high percentage of tumor tissues of diversified cancer types, including liver, esophagus, colon, gastric, lung, prostate, cervical, and breast cancer.Synonyms: BCSG1, Breast cancer-specific gene 1 protein, PERSYN, PRSN, Synoretin, Synuclein gamma