A study of chromosome aneuploidy in hereditary breast cancer patients and their healthy blood relatives

Chromosomal abnormalities that may predispose a group of individuals to dev elop certain neoplasms have been reported in lymphocytes. We evaluated cyto genetic abnormalities in 21 histopathologically confirmed primary breast ca ncel patients (BCPs), 52 healthy blood relatives (HBRs), belonging to 19 he reditary breast cancer families (HBFs) and 25 females as control. Phytohema gglutinin stimulated peripheral blood lymphocyte (PBL) cultures were used t o study the chromosomal abnormalities in BCPs and their HBRs. Short term cu lture of the tumor tissue was also carried out in defined growth medium. Su itable metaphases (11 to 55) from tumors and a minimum of 100 metaphases fr om PBL were karyotyped for the cytogenetic analysis. Heterogeneous populati on of cells with random and nonrandom chromosomal abnormalities was noticed in tumors. In control groups 2-5% of metaphases showed numerical abnormali ties, whereas this phenomenon was observed in 3-18% of metaphases in HBRs a nd 3-23% of metaphases in BCPs. In tumor tissue, 47.05% of BCPs showed nume rical abnormalities in more than 16 metaphases. In lymphocytes, this event was observed in 33.33% of BCPs and 13.14% of HBRs. In controls 1.28%, in BC Ps 52.04% (tumor) and 13.42% (lymphocytes), and in HBRs 9.03% of metaphases were found aneuploid. Statistically it was highly significant (Fisher's ex act test, P<0.00001). In lymphocytes of BCPs, chromosomes 1, 6, 8, 9, 15, 1 7, 18, 20, and X and in HBRs, chromosomes 8, 15, 17, is, and X were frequen tly involved. It can be inferred from the findings that the above mentioned chromosomes may have an important role in early stage of breast carcinogen esis in BCFs. Moreover, presence of similar abnormalities in HER indicates inherited pattern of this genetic error among them.