SKP2 and neoplasm: Previous reports have demonstrated that ATO inhibited pancreatic xenografted tumor growth by decreasing proliferation and increasing apoptosis in vivo [17,25] and that ATO suppressed PC cell proliferation and migration by downregulation of S-phase kinase-associated protein 2 (Skp2) [14], a cell cycle regulator playing oncogenic roles in cell growth, apoptosis, migration/invasion and angiogenesis [26], and chemoresistance [14,27,28].