Notably, 3-fold bigger tumors were developed in Hpa2-KO pancreas than in control (wt) pancreas (Fig. 7A; 0.4 ± 0.1 gr vs 1.2 ± 0.15 gr for wt vs Hpa2-KO tumors, respectively; p = 0.004), indicating that host-derived Hpa2 is critically important and functions to restrain tumor growth. Here, HPSE2 is linked to neoplasm.