[Molecular analysis of chronic Philadelphia chromosome negative myeloid leukemia: study of 6 cases].

BACKGROUND

Patients with Philadelphia negative (Ph-) chronic myeloid leukemia (CML) constitute a small proportion of the total number of patients with CML. Molecular analysis of these cases has permitted recognition that some cases present a breakpoint in the bcr region of chromosome 22, that is, the alteration constituting the substrate of the Ph chromosome. To date, the number of patients analyzed to this regard is low.

METHODS

Six patients with Ph negative CML who constituted part of a series of 96 patients diagnosed with CML over a period of 6 years were studied. Analysis of the BCR gene in the DNA of the leuko-concentrate of peripheral blood was carried out with the Southern Blot technique, using the 3' and 5' probes and Transprobe and the restriction enzymes Bgl II, Eco RI, Hind III and Bam HI. The principal clinical-hematological characteristics of the patients were analyzed.

RESULTS

Breakpoints were observed in the bcr region of chromosome 22 in 3 of the 6 patients, all of whom presented typical CML clinical-hematological features.

CONCLUSIONS

Half of the patients with Philadelphia negative (Ph-) chronic myeloid leukemia (CML) have a breakpoint in the bcr region of chromosome 22, a similar molecular pattern to the Ph positive CML and their clinical-hematological profile is indistinguishable from those with CML.