DNA ANEUPLOIDY IN EARLY BREAST-CANCER

High-resolution flow cytometric (FCM) DNA analysis was performed on 14 8 unfixed, frozen tissue samples from four groups of early breast canc ers: invasive carcinomas (ICs) with predominance of carcinoma in situ (DCIS) (group I), small clinical cancers less than or equal to 15 mm ( group II), node-negative, clinical cancers (group III) and small scree ning-detected cancers less than or equal to 15 mm (group IV). The medi an tumour size was 12 mm. The aim of the study was to support, with a larger sample, our recent findings with respect to DNA ploidy pattern in the selected group of ICs with predominance of DCIS (group I). Simi lar results to this group were found for both the small clinical cance rs and the node-negative cancers, with respect to frequency of DNA ane uploidy (79% and 90%), DNA index (DI) distribution, intratumoral DNA h eterogeneity and S-phase fraction. A high frequency of DNA hyperdiploi d clones was found, in particular related to highly differentiated tum ours. A significant difference was found compared with the screening-d etected cancers, which were characterised by a much lower frequency of DNA aneuploid samples (49%) and may represent a biologically specific group of low-malignant, slowly growing tumours. Associations were sho wn between histological grade and DI subclasses, and between lymph nod e status and DNA diploidy/aneuploidy, whereas DI was not correlated wi th tumour size. The DNA ploidy findings in this series of early cancer s are concordant to our own results from preinvasive lesions as well a s those reported from series of more advanced cancers.