Abstract: The aim of the study was to correlate the DNA Index (DI) and S‐phase fraction (SPF) values determined by multiparametric flow cytometry in breast cancer (mainly T1 and T2 stages) with several clinico‐pathologic variables and other biological parameters. For this purpose, a total of 136 breast cancers were submitted to flow cytometry and to several types of immunohistochemical analyses. Among clinico‐pathologic data we considered pT, pN and grade and among immunohistochemical markers, hormonal receptors, P53, c‐erbB‐2 and MIB‐1. We found that DNA aneuploidy was strongly correlated with high tumoral grade, absence of hormonal receptors, high proliferation, as shown by high MIB‐1 ({\scriptstyle\geq}36%) and SPF values ({\scriptstyle\geq}13.3%), and P53 positivity. Grouping the tumours according to their DI values, we observed a relative significantly higher correlation of the near‐triploid range carcinomas (DI 1.40–1.60) with immunohistochemical expression of P53 (p=0.0001). Near‐triploid DI was also associated with a high proliferative activity, expressed both by SPF (p=0.0001) and MIB‐1 reactivity (p=0.0001), high tumoral grade (p=0.0001) and presence of axillary metastases (p=0.03). These data suggest that DNA near‐triploid tumours in breast cancer may have a more aggressive behaviour in comparison with other DI classes.
Keywords: Ploidy, breast cancer, P53, prognostic markers
