RELATIONSHIP BETWEEN MDR-1 GENE-EXPRESSION AND AG-NOR PATTERN IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

Diagnostic marrows from 12 relapsed and 7 cALL patients in remission a t 1 year off treatment were compared for Silver stainable Nucleolar Or ganising Regions (Ag-NOR's) and Multi Drug Resistance Gene-1 product ( p-170 glycoprotein) expression using routine immunocytochemistry and b lind, repeated assessment. The mean total, mean number of large Ag-NOR 's, and mean area of 5 largest Ag-NOR's per nucleus for each patient w as calculated. P-170 expression was graded semiquantitatively. Reprodu cibility was >90%. Groups were compared using Mann-Whitney two-tailed test. The mean total Ag-NOR number, mean number of large Ag-NORs, mean area of five largest Ag-NORs as well as p-170 expression score was hi gher in the relapse group (p < 0.05). Relapsed patients had high mean total Ag-NOR number (mean 4.42, range 2.96-6.24) and/or high p-170 sco re (mean 2.25, range 1-3.5) whereas remission patients had lower Ag-NO R number (mean 3.32, 2.22-4.20) as well as lower p-170 (mean 1.86, ran ge 1-3.5) score. Two isolated extra-medullary relapse patients had bot h lower Ag-NOR and p-170 scores. The results justify further studies i nto the cellular basis of this relationship and the prognostic value.