Letter: A new consistent chromosomal abnormality in chronic myelogenous leukaemia identified by quinacrine fluorescence and Giemsa staining.

Abstract

CELLS from nine consecutive patients with chronic myelogenous leukaemia (CML) have been analysed with quinacrine fluorescence and various Giemsa staining techniques. The Philadelphia (Ph1) chromosome in all nine patients represents a deletion of the long arm of chromosome 22 (22q−)1,2. An unsuspected abnormality in all cells from the nine patients has been detected with these new staining techniques. It consists of the addition of dully fluorescing material to the end of the long arm of one chromosome 9 (9q+). In Giemsa-stained preparations, this material appears as an additional faint terminal band in one chromosome 9. The amount of additional material is approximately equal to the amount missing from the Ph1 (22q−) chromosome, suggesting that there may be a hitherto undetected translocation between the long arm of 22 and the long arm of 9, producing the 9q+ chromosome.