Double minute chromosomes in the leukocytes of a young girl with breast carcinoma.

Cytogenetic analysis was performed in a young girl with breast carcinoma. The most important finding was the existence of double minute (dmin) chromosomes, besides other chromosomal abnormalities. Removal of the tumor resulted in reduction of chromosomal abnormalities in the leukocyte cultures repeated after 1 year, suggesting that the presence of tumor may elevate the frequency of chromosomal abnormalities. The presence of dmin chromosomes indicates that factors causing their presence in tumor cells may also operate in human leukocytes.