[Cytogenetic and molecular studies in patients with chronic myelogenous leukemia without Ph chromosome and with...

Cytogenetic and molecular studies were made in 4 patients with Ph negative chronic myelogenous leukemia (CML) and 4 patients with CML with unusual Ph translocation. Chromosome analysis was performed on direct preparations and short-term cultures of bone marrow cells by R and G bandings. Southern blot analysis of DNA from leukemia cells was made using 4.5kb bcr-u and 1.5kb bcr-HE probes. Four patients with Ph negative CML had normal karyotypes. Among them, 3 had rearrangement of bcr, and 1 expected germ line pattern only. In the 4 patients with CML with unusual Ph translocation who had bcr rearrangement, one had a masked Ph chromosome originating from a translocation t(3;22) (p22;q11), the other three had one of the following complex Ph translocations: t(9;22;13) (q34;q11;q21), t(3;14;22) (p21;q32;q11) and t(X;9;22;12) (q22; q34; q11; q24). Our data confirmed that Ph negative CML could be divided into two different subsets: Ph-bcr+ CML and Ph-bcr-CML and that whatever the type of translocation may be, CML with unusual Ph translocation and Ph positive CML had a common molecular pathological basis.