INTERSTITIAL 9Q DELETION IS ASSOCIATED WITH CD7(-LEUKEMIA OF MYELOID AND T-LYMPHOID LINEAGE() ACUTE)

We report the clinical, hematological and immunophenotypic characteris tics from four cases of acute leukemia with interstitial deletion of c hromosome 9, ie del(9)(q12-q22), as a single chromosomal abnormality. Three patients half acute myeloblastic leukemia (AML) and one T origin acute lymphoblastic leukemia (ALL). According to FAB classification, blasts were classified as M1 (two patients). M2 (one patient), and L2 (one patient). In two out of three AML cases a myelodysplastic syndrom e, one AREB-t and one AREB diagnosed 6 and 11 months before respective ly, preceded the onset of AML. Morphological examination showed dysgra nulopoiesis, dyserythropoiesis and cytoplasmic vacuoles in two AML pat ients, while a strong positivity to myeloperoxidases was observed in a ll AML cases. As concerns immunophenotypic findings, blast cells from two of three AML patients expressed CD7 and CD34, while those from the T-ALL case displayed CD33 and CD34 along with CD7. These observations suggest that del (9q) is associated with CD7(+) acute leukemia of mye loid or lymphoid lineage.