Cytogenetic analysis of metastatic effusions from breast tumors.

Chromosome analysis was performed on direct and in vitro cultures of 30 effusions from breast carcinoma. Although in 14 samples normal diploid stem-lines were found, chromosome abnormalities were present in stem- or side-lines of all cases. Recurrent numerical deviations were only verified as gains of Nos. 6 and 7. Rearrangements were seen involving almost all chromosome pairs (except No. 18 and gonosomes), however, Nos. 1, 3, 6 and 11 were those most frequently related to the genesis of markers. Double minutes (DMs) were found in seven samples, and there was a homogeneously staining region (HSR) in one.