Interstitial 9q- deletions in hematologic malignancies.

Sixteen patients with interstitial deletions of the long arm of chromosome #9 (9q-). were studied. From our observations and the findings of ten other cases in the literature, it can be deduced that the anomaly is almost exclusively found in myeloproliferative disorders and that it rarely occurs as the sole anomaly; however, in more than one-third of the cases, it was associated with a t(8;21) and occurred as a secondary event. The deletion appears to be interstitial, the breakpoints are somewhat variable, and the region carrying the abl oncogene was never involved.