BTG3 and systemic sclerosis: Intracellular targets of SSc-associated ANA include topoisomerase-I (TOPO-I), centromeric proteins (CENP), polymerase enzymes such as RNA polymerase III (RNAP), ribonuclear proteins (U3 RNP/anti-fibrillarin, U1 RNP, U11/U12 RNP), or less frequently nucleolar antigens (Th/To, SS-A, and SS-B, NOR 90, Ku, RuvBL1/2, and PM/Scl) (11).