Clinical findings and HER-2/neu gene amplification status of breast carcinoma patients.

The study group was derived from the archival materials of 48 invasive intraductal breast cancer patients who had undergone partial mastectomy/ axillary dissection. All patients included in the study had clinically T1-2N0M0 invasive ductal carcinoma. To detect HER-2/neu status, fluorescent in situ hybridization was performed using a HER-2/neu locus-specific probe. Signals were counted and patients were classified in three groups according to signal ratios: signal ratio <2, group 1 (n=31); signal ratio 2-4, group 2 (n=11); signal ratio >4, group 3 (n=6). Ratios of axillary metastatic lymph nodes to dissected total lymph nodes were 17%, 23% and 83% in groups 1, 2 and 3 respectively (P=0.003). The number of metastatic axillary lymph nodes, and the ratio of microscopic metastatic lymph nodes were highest in group 3 (P=0.001 and P=0.008, respectively). No significant difference was observed between groups for distant metastasis in a 5-year follow-up period. Signal ratios decreased with estrogen receptor expression (P=0.03). Histopathologically, an irregular growth pattern of the tumor was observed in 100% of the patients in group 3, and in 54% and 60% in groups 1 and 2, respectively (P=0.04). Lymphovascular invasion of the tumor was significantly higher in group 3 compared to the other two groups (P=0.01). The extensive intraductal component ratio was the highest in group 3 (P=0.04). The appearance of desmoplastic reaction and lymphocyte infiltration did not show significant difference between the groups. Our results show that HER-2/neu signal ratio increases with lymphovascular invasion, an extensive intraductal component, irregular growth pattern and axillary metastasis in clinically T1-2N0M0 invasive ductal carcinoma of the breast.