PROGNOSTIC ASSOCIATION OF C-ERBB-2 ONCOGENE AMPLIFICATION AND PROTEINOVEREXPRESSION IN HUMAN BREAST-CANCER USING ARCHIVAL TISSUES - A COMPARATIVE-STUDY

The prognostic associations of c-erbB-2 gene amplification analysed by dot-blot hybridization and of c-erbB-2 protein overexpression assesse d by immunohistochemistry (IHC) were compared in 161 patients with ope rable breast cancer using formalin fixed paraffin embedded archival ti ssues. The efficiency of the dot-blot technique to detect c-erbB-2 amp lification was first validated by comparing the results of dot-blot wi th those of Southern blot hybridization in 134 tumour samples and ther e was an excellent correlation. In the main series of 161 samples, whe re results of IHC and dot-blot were compared, 35.4% showed c-erbB-2 ov erexpression and 17.4% showed gene amplification. Tumours showing over expression of c-erbB-2 protein had a significantly shorter disease-fre e survival (DSF) and survival(s) compared to tumours showing no overex pression. A multivariate analysis revealed that c-erbB-2 overexpressio n was independently correlated with poor prognosis. On the other hand, no significant association between c-erbB-2 gene amplification and DF S or S was observed. We conclude that c-erbB-2 protein overexpression assessed by IHC is a superior prognostic indicator in operable breast cancer compared to c-erbB-2 gene amplification analysed by the dot-blo t technique.