High-resolution flow cytometric (FCM)
DNA analysis was performed on 148 unfixed, frozen tissue samples from four groups of early breast
cancers: invasive
carcinomas (ICs) with predominance of
carcinoma in situ (
DCIS) (group I), small clinical
cancers < or = 15 mm (group II), node-negative, clinical
cancers (group III) and small screening-detected
cancers < or = 15 mm (group IV). The median 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). Similar results to this group were found for both the small clinical
cancers and the node-negative
cancers, with respect to frequency of
DNA aneuploidy (79% and 90%),
DNA index (DI) distribution, intratumoral
DNA heterogeneity and S-phase fraction. A high frequency of
DNA hyperdiploid clones was found, in particular related to highly differentiated tumours. A significant difference was found compared with the screening-detected
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 shown between histological grade and DI subclasses, and between lymph node status and
DNA diploidy/
aneuploidy, whereas DI was not correlated with tumour size. The
DNA ploidy findings in this series of early
cancers are concordant to our own results from preinvasive lesions as well as those reported from series of more advanced
cancers.