c-erbB-2 Amplification in Node-Negative Human Breast Cancer

c-erbB-2 gene analysis by Southern and DNA dot blot methods was done in 66 tumor samples from patients with histologically node-negative breast cancer. The c-erbB-2 gene was amplified 2- to >8-fold in 13 tumors (20%). None of 59 tumors that were examined by the Southern method showed c-erbB-2 gene rearrangement. c-erbB-2 amplification was analyzed in relation to other prognostic factors. The c-erbB-2 gene was amplified in five of 36 (14%) diploid and eight of 30 (27%) aneuploid tumors. Thirteen of 54 (24%) tumors with nuclear Grade 1 or 2 displayed c-erbB-2 amplification, whereas none of 12 tumors with nuclear Grade 3 did. No correlation was observed with estrogen receptor content, tumor size, histological type, or age of patients. The median follow-up date for these patients was 85+ mo. Of 13 patients whose tumors showed c-erbB-2 amplification, six patients (46%) developed recurrence, and five patients (38%) died of metastatic disease. In contrast, of 53 patients whose tumors did not show c-erbB-2 amplification, 15 patients (28%) developed recurrence, and seven patients (13%) died of disease. In conclusion, our results show that c-erbB-2 gene amplification was more frequent in aneuploid tumors and tumors with poor nuclear grade. c-erbB-2 amplification may be considered a possible prognostic factor in node-negative breast cancer.