HPSE2 and neoplasm: Immunostaining further revealed that Hpa2-tumors exhibit a higher rate of cell proliferation indicated by a two-fold increase in Ki67-positive cells (Supplementary Fig. 5A, lower panels), whereas halted tumor growth by Hpa2-Nuc cells is associated with substantial recruitment of macrophages (F4/80; Supplementary Fig. 5A, third panels).