Cytogenetic description of breast fibroadenomas: alterations related solely to proliferation?

Abstract

Twelve breast fibroadenomas were analyzed cytogenetically and only four were found to have clonal alterations. The presence of chromosomal alterations in fibroadenomas must be the consequence of the proliferating process and must not be related to the etiology of this type of lesion. In contrast, the few fibroadenomas that exhibit chromosomal alterations are likely to be those presenting a risk of neoplastic transformation. Clonal numerical alterations involved chromosomes 8, 18, 19, and 21. Of the chromosomal alterations found in the present study, only monosomy of chromosomes 19 and 21 has been reported in breast fibroadenomas. The loss of chromosome 21 was the most frequent alteration found in our sample. The study of benign proliferations and their comparison with chromosome alterations in their malignant counterparts ought to result in a better understanding of the genes acting on cell proliferation alone, and of the genes that cause these cells to exhibit varied behaviors such as recurrences, spontaneous regression and fast growth.

Cytogenetic changes in nonmalignant breast tissue

“…Cavalli et al (2001) used culture methods that favor the mesenchymal part of the tissue (serum-rich medium). The types of chromosome aberrations in fibroadenomas we found are similar to those found in other studies; monosomies were frequent, including Ϫ19, Ϫ3, and Ϫ18 (Tibiletti et al, 2000;Burbano et al, 2001;Cavalli et al, 2001). The breakpoints 6p21 and 17q25 in case B3 (Table 1) have also been reported in benign and malignant tumors (Pandis et al, 1993;Dietrich et al, 1995;Rohen et al, 1996;Polito et al, 1998).…”

Investigation of chromosome 21 aneuploidies in breast fibroadenomas by fluorescence in situ hybridisation

“…All samples were analysed by classical cytogenetics: 12 cases had been previously evaluated by our research group [8] and 3 are presented in this study (Table 1). In the present study, cell suspension preparations from all cases were analysed by FISH.…”

“…The aim of this study was to investigate numerical alterations of chromosome 21 in breast FAs by FISH. Previously, our laboratory found a high incidence of chromosome 21 monosomy in breast FA [8]. Possible correlations between these findings and histopathological characteristics were also evaluated and may result in prognostic parameters in this neoplasia.…”

“…Data from the literature show that clonal alterations involve chromosomes 1, 4, 6, 12, 17 and 20 in structural rearrangements, and chromosomes 5,8,11,12,16,17,18,19,20 and 21 in aneuploidies [3,4,7,8]. Most FAs do not exhibit any detectable cytogenetic abnormalities [4].…”

“…Histological diagnosis, chromosomal alterations by GTG banding technique and FISH analyses of interphase nuclei for chromosome 21 copy number Burbano et al[8] um bromide. Molecular cytogenetic analysis was carried out under an Olympus BX41 fluorescence microscope with double FITC/TRICT filter (Olympus, Japan) and an Applied Spectral Imaging image analysis system (ASI Ltd., Israel).…”