The inhibition of proliferation was shown as % cell growth inhibition induced by cetuximab selleck inhibitor or/and trastuzumab in comparison with that induced by control mAb. Survival analysis Actuarial overall survival rates were analysed by the Kaplan�CMeier method, and survival was measured in months from operation to death or the last review. The log-rank test was applied to compare the two groups. Statistics To evaluate significant differences between groups, Student’s t-test was performed. Significance was considered at P<0.05. RESULTS Frequencies and patterns of EGFR and HER-2 expression in oesophageal SCC Sixty-six oesophageal SCC tumours were examined for both EGFR and HER-2 expression in serial sections by IHC. EGFR-positive expression was observed in 22 cases (33%), while HER-2-positive expression was noted in 20 cases (31%).

Both EGFR and HER-2 expressions in the same patients were observed in 12 cases (18%) (Figures 1 and and2),2), in which expressions of both EGFR and HER-2 were seen in the same tumour regions in two cases (Figure 1), and EGFR and HER-2 expressions were seen in individually distinct regions in nine cases (Figure 2). The data of EGFR and HER-2 expression in oesophageal SCC indicated that 45% of the patients showed either EGFR or HER-2 expression, and 18% of the patients showed both EGFR and HER-2. Of both EGFR- and HER-2-positive cases, 75% showed EGFR and HER-2 expression in individually distinct regions. Figure 1 Immunohistochemical staining of EGFR and HER-2 in oesophageal SCC. In oesophageal SCC, EGFR and HER-2 expressions were evaluated by IHC in the serial sections.

Representative stainings for EGFR (A) and HER-2 (B) are shown, and both expressions were seen … Figure 2 Immunohistochemical staining of EGFR and HER-2 in oesophageal SCC. In oesophageal SCC, EGFR and HER-2 expressions were evaluated by IHC in the serial sections ( �� 100). The region with EGFR-positive expression (A) was negative for HER-2 (B) in … Furthermore, distribution of the grading of IHC for EGFR and HER-2 is shown in Table 2, indicating that there were variable patterns in their grading. Table 2 Grading patterns of HER-2 and EGFR expression in oesophageal SCC (n=66) Oesophageal SCC patient survival in relation to EGFR and HER-2 expression There was a tendency that the survival rate of patients with both EGFR (+) and HER-2 (+) was lower than those with EGFR (?) and HER-2 (?), although it was not significant (Figure 3).

Figure 3 Survival curves of the patients with oesophageal SCC in relation to EGFR and HER-2 expression. Actuarial overall survival rates were analysed by the Kaplan�CMeier method, and survival was measured in months from operation to death or the last review. … Synergistic antiproliferative effect of cetuximab and trastuzumab against oesophageal SCC We have reported previously six different oesophageal SCC cell lines with variable expressions of HER-2 GSK-3 (Mimura et al, 2005a).