HPSE2 and neoplasm: In order to further investigate the role of nuclear Hpa2 on tumor growth, we selected ZR-75-1 cell clones that express high levels of Hpa2-Nuc (#27, #31) (Supplementary Fig. 5B) and compared their tumorigenic capacity to cell clones that were selected randomly from control (Vo) cultures (#2, #5, #6).