[Immunohistochemical analysis of p53 and c-erbB-2 in breast cancer]

We have studied by immunohistochemistry the nuclear expression of p53 and the finding of oncoprotein c-erbB-2 in a series of 85 breast carcinomas. The tissue was fixed in buffered formalin and embedded in paraffin. The primary antisera were obtained from Biogenex (USA), Bp53-12, monoclonal, used in a dilution of 1:100 for p53 and from Triton Diagnostics (USA), pAB-1, polyclonal, used in a dilution of 1:200 for c-erbB2. The detection system was the Vectastain Elite kit obtained from Vector Laboratories (USA). The results were compared with several morphological features of the tumors such as size and type of the tumor, extension of the intraductal component, nuclear grade, axillary lymph node metastasis and estrogen receptor data as well as with total and disease free survival. The oncoprotein p53 was detected in the nuclei in 25 (29.4%) of our cases (Fig 1). Its presence was correlated with tumor size (p < 0.01), high nuclear grade (p < 0.0001) and estrogen receptor negative tumors (p < 0.0001). There was an inverse relationship between p53 expression and 5 year disease free survival (p < 0.005). In 21 (24.7%) of the cases we found amplification of c-erbB-2. The staining pattern was membranous (Fig. 2). It was correlated significantly with the ductal type of invasive carcinoma (p < 0.05), an associated extensive intraductal component (p < 0.001), estrogen receptor negative tumors (p < 0.0001) and shortening of disease free survival in the patients with positive axillary lymph nodes (p < 0.005). In 9 cases we found staining for both markers without statistically significant relationship with the other features studied. We conclude that the presence of these genetic alterations demonstrated by immunohistochemistry were, in our series, unfavourable prognostic factors in invasive breast cancer.