Established s.c. tumors from HCC SMMC-7721 and BEL-7404 cells. The cells were suspended in 100 μl of RPMI 1640 complete culture with 25% Matrigel (BD Biosciences) and subcutaneously implanted into the left flanks of 4-week-old nude mice. When the s.c. tumors were palpable, mice were inoculated into the s.c. tumor twice a week with 2 × 107/50 ul of G47Δ or virus buffer [150 mM NaCl, 20 mM Tris, (pH 7.5)] for control. H-E staining of SMMC-7721 (A) and BEL-7404 (C) s.c. tumors (×200). Coronal sections through SMMC-7721 (B) and BEL-7404 (D) s.c. tumors 3 days after G47Δ (2 × 107 pfu) injection to illustrate the virus replication in the s.c. tumors. Sections were stained with X-gal, and counterstained with eosin to identify cells containing replicating G47Δ (blue).