C-ERBB-2 NEU PROTEIN EXPRESSION, DNA-PLOIDY AND S-PHASE IN BREAST-CANCER/

DNA content and c-erbB2/neu protein (p185) expression were evaluated b y flow-cytometry and ELISA, respectively, in 166 specimens of primary breast cancer. A non-diploid DNA content was found in 88 tumours (53%) , with the DNA index ranging from 0.7-2.7. S phase fraction (SPF) eval uation, performed in 130 cases, showed significantly higher values in aneuploid than in diploid tumours (median values, 17.3% and 5.8%, resp ectively). Thirty-six tumours (21.6%) showed p185 overexpression, whil e 45 (27.1%) and 85 (51.3%) showed intermediate and low expression, re spectively. A good correlation (P=0.0023) was found between DNA conten t and p185 positivity. Tumours with high p185 values were mainly aneup loid, while tumours with intermediate or low expression had variable d egrees of DNA content. Furthermore, p185 concentration was significant ly higher in aneuploid than in diploid tumours (P=0.009). The highest rate of p185 (+) cases and the highest p185 concentrations occurred in triploid (1.3<D.I.less than or equal to 1.7), compared to the other t umours. SPF values and p185 positivity rates were not significantly co rrelated in diploid and in aneuploid tumours.