HPSE2 and neoplasm: Interestingly, even more efficient inhibition of tumor growth was obtained with SiHa cells transfected with the Pro140Arg (hereafter 140) and Asn543Ile (hereafter 543) Hpa2 mutants (Fig. 1B; P < 0.0001 and P < 0.0001 for 140 vs WT and 543 vs WT, respectively; P < 0.001 and P < 0.001 for 140 and 543 vs wt, respectively).