Trisomy 8 and 18 as frequent clonal and single-cell aberrations in 185 primary breast carcinomas

For cytogenetic investigations short-term cultures of 185 breast carcinomas (135 invasive ductal, 21 invasive lobular, 12 invasive ductal with intraductal components, seven heterogeneous, six intraductal, four invasive ductal and lobular) were prepared. Cytogenetic examinations revealed clonal abnormalities in 39 cases with a predominance of simple numerical chromosome changes, i.e., trisomies of chromosomes 7, 8, and 18. One hundred forty-six tumors did not show clonal abnormalities, but single-cell aberrations other than monosomies occurred in 79 of these tumors. Compared to cells of epithelial hyperplasia of the breast, amniotic fluid cells, and cells from pleomorphic adenomas cultivated using the same medium, the frequency of single-cell trisomies was significantly higher. Trisomy 8 was not only found as a clonal aberration in 10 cases but was also the most frequent non-clonal aberration. Trisomy 7 and 18 were also frequent clonal as well as non-clonal cytogenetic deviations.