Ductal breast carcinomas with whole chromosome gains as a particular subset of near-diploid tumors with different metastasis free survival.

We recently proposed the existence of a subtype of slightly hyperdiploid ductal breast cancers with cytogenetic alterations differing from those usually observed in the majority of these tumors. We aimed to establish whether these tumors, which represent about 50% of those with a DNA index (DI) comprised between 1.1 and 1.

Ductal breast carcinoma develops through different patterns of chromosomal evolution.

In a previous study that used comparative genomic hybridization (CGH) to analyze 43 ductal breast carcinomas selected for hyperdiploidy, we proposed the existence of two distinct pathways of chromosomal evolution. In the present study, in which we reassessed our cytogenetic findings on 158 ductal breast carcinomas selected for having a modal number of chromosomes of fewer than 60, we confirmed the existence of two subtypes of tumors. Along with the great majority of tumors (142 of 158) that evolved through structural rearrangements with no or very few whole-chromosome gains, we found that a minor subset (16 of 158) evolved through progressive gains of whole chromosomes with no or only a few associated rearrangements.

Characterization of a new cytogenetic subtype of ductal breast carcinomas.

About 50% of ductal breast carcinomas do not yield analysable karyotypes after short-term culturing. Comparison of the cytogenetic subset to the whole data set of tumors revealed that slightly hyperdiploid tumors, that is, with DNA index between 1.05 and 1.

Potential rapid assessment of breast cancer prognosis using induced chromosome condensation performed on cytological specimens.

We have previously shown that assessment of chromosome alteration rate by cytogenetics is well correlated with breast cancer prognosis factors. As karyotypes are usually difficult to obtain from solid tumors using conventional methods, a new approach is proposed. Metaphase-like chromosomes were directly obtained following chromosome condensation using calyculin A (okadaic acid) from cytologic specimens of breast cancers sampled by fine needle.