Purpose: Oncogen or growth factor receptor such as phospholipase C isoenzyme r-1 (PLC r-1), epidermal growth factor receptor (EGFR), and Her-2/neu which related with tyrosin kinasemay and then regulating vell proliferation may have a role as prognostic factors for breast cancer. Material and Methods: With assumption that expression of PLC r-l, EGFR and Her-2/neu oncogene has close relationship with prognosis of breast cancer, 59 breast cancer patients who were operated upon at Korea University Hospital during a period of 6 years starting June 1988 to May 1994 were selected for this study. This study was carried out by comparing between expression of PLC r-l, EGFR and Her-2/neu oncogene and patients survival rate. These expression were also compared with TNM system, estrogen and progesterone receptor and at same time these expressions were compared with each other to see whether there are any relationship among these expression. Results) Expression of PLC r-1, EGFR and Her-2/neu were present in 42%(25/59), 46%(27/59) and 20%(12/59). The expression of PLC r-1 was closely related with the expression of EGFR(p<0.05) and Her-2/neu (p<0.05), but there were no relationship between the expression of PLC r-1 and hormonal receptors and TNM stage(p>0.05). The expression of EGFR was closely related with the expression of Her-2/neu(p<0.05) and hormone receptors(p<0.05), but there were no relationship between the expression of EGFR and pathologic TNM stage(p>0.05). The expression of Her-2/neu was not closely related with hormone receptors and TNM stage except axillary lymph node metastasis. There were close relationship between overall and disease free survival and PLC r-1 and Her-2/neu. But EGFR had only related with disease free survival rate. Conclusion: In conclusion, the expression of PLC r-1, EGFR and Her-2/neu oncogene in human breast cancer may be useful prognostic factors independently and it may potentiated its individual value as a prognostic factors if use them together.