Abstract

Overexpression of c-erbB-2 oncoprotein has been shown to correlate with poor prognosis and drug-resistance to the conventional chemotherapy with 5-fluorouracil in breast and gastric cancers. To evaluate the clinical significance of c-erbB-2 overexpreseion in colorectal cancer, immunohistochemical staining was performed with the paraffin-embedded tiasues of 141 colorectal cancer patients with curative surgery. The follow-up duration ranged from 7 to 61 months(median 30 months). Two-year disease- free and overall survival rate of the total patients were 77%, 91%, respectively. The c-erbB-2 positive rate was 24.8%, Even if patients with c-erbB-2 overexpression showed a tendency of poor prognosis than c-erbB-2 negative patients, T-factor and the TNM stage were independent prognostic factors in multivariate analysis. In subset analysis with c-erbB-2 negative patienta, there were no differences in recurrence rate and 2-year disease-free survival rate between pa- tients with chemotherapy and without chemotherapy(20.0% versus 26.1%)(80.0% versus 82.0%). However, in c-erbB-2 positive patients, those subgroup with chemotherapy showed tendencies toward advantages in relapse rate and 2-year disease-free survival rate than those of subgroup without chemotherapy(21.0% versus 50.0%; p=0.09)(76.0% versus 50.0%: p=0.06). Also, there was a tendency of increased time to relapse in patients with chemotherapy comparing to that of the patients without chemotherapy(7.5 months versus l7.0 months; p = 0.09). In stage III, patients with c-erbB-2 overexpression showed increased 2-year disease-free survival rate with chemotherapy as comparing to that of patients without chemotherapy(81.0% versus 29.0%; p= 0.003). Again, this survival benefit was not found in c-erbB-2 negative stage III patients regard- less of chemotherapy. In conclusion, c-erbB-2 overexyression might be a marker of relative drug resistance to 5-FU which will be converted with the high dose treatment of modulation with leucovorin. A prospective randomized trial is warrented to confirm this suggestion and for the clinical applica- tion of c-erbB-2 overexpression.

• Keywords: c-erbB-2, Colorectal cancer, Drug-resistance, 5-fluorourecil and leucovorin