Differences in oestrogen and progesterone receptors, HER-2, p53 expression and proliferation in ductal breast cancers in relation to histopathological grade.
In case of breast cancer the grade of differentiation and expression of oestrogen and progesterone receptors falls within the first category of prognostic factors according to the College of American Pathologists. HER-2, p53 and Ki67 belong to the second category and their significance still awaits confirmation. The aim of the present study was to examine the relationship between the intensity of expression of oestrogen receptors (ER), progesterone receptors (PgR), HER-2, p53 and Ki67 in cells of ductal breast cancer of G1, G2 or G3 differentiation grade. In paraffin sections of 60 ductal breast cancers (20 cases in G1, 20 in G2 and 20 in G3), immunocytochemical reactions were performed to detect the expression of ER, PgR, HER-2, p53 and Ki67. Following a semi-quantitative appraisal of the preparations under examination, appropriate statistical tests were used to document significant relationships. We noted significant positive correlations between ER and PgR (the entire group studied, G1-3, and the G1 group), HER-2 and p53 (G2) and between p53 and Ki67 expression (G2). Significant negative correlations were found between ER and p53 (G1-3), PgR and p53 (G1-3, G1, G3) and between PgR and Ki67 (G1-3, G2). The studies performed demonstrated distinct relationships between the expression intensity of various proteins in tumour cells in relation to the grade of differentiation of the tumour. We also showed that a parallel determination of ER, PgR and p53 expression may carry high predictive value as to response to tamoxifen treatment.