Figure 5.

Growth inhibition by trastuzumab in HER2-overexpressing cells both in vitro and in vivo. (A) Growth inhibition by trastuzumab in various gastric cancer cell lines. Cells were plated in 24-well dish and treated twice with increasing doses of trastuzumab, followed by cell counting after a 4-day culture. (B) Inhibitory effects of gefitinib, trastuzumab and combination therapy on the growth of HER2-overexpressing (GLM-1) and low-expressing tumour (MKN-45) xenografts in nude mice. Tumour cells were injected subcutaneously into nude mice (n=5∼6) and gefitinib (150 mg per kg per day, oral administration, five times per week for 6 weeks), trastuzumab (20 mg per kg per day, intraperitoneal injection, twice a week for 6 weeks) and the combination was administered. ^*P<0.01, ^**P<0.001 (vs control). Bars=s.e.