The incidences of trisomy 8, trisomy 9 and D20S108 deletion in polycythaemia vera: an analysis of blood granulocytes using interphase fluorescence insitu hybridization

We have used interphase fluorescence in situ hybridization (IFISH) to detec t trisomy 8, trisomy 9 and 20q deletion in circulating granulocytes from pa tients with polycythaemia vera (PV). Out of 64 PV patients, 15 (23%) exhibi ted an abnormality. Two patients had trisomy 9, three had trisomy 8 and 10 patients had hemizygous deletion of D20S108 (a locus in the 20q common dele ted region). Aberrant nuclei ranged from 10% to 80% in these 15 cases. Ther e was no correlation between the presence of a marker and sex, age, interva l between presentation and IFISH analysis, neutrophil or platelet count or therapy. Conventional marrow cytogenetic karyotype results were available i n 23 cases and there was concurrence between these and blood IFISH in 16 ca ses (13 normal and three with 20q/D20S108 deletion by both methods). Three patients with D20S108 deletion by IFISH were normal by previous marrow cyto genetic testing and four cases with 20q deletion by previous marrow cytogen etics had normal blood granulocytes according to IFISH. Thus, we confirm th at trisomies 8 and 9 and deletion of 20q are diagnostically useful markers of PV. IFISH analysis of blood granulocytes is a practical method for detec ting these markers, but as an adjunct to, not as a substitute for, conventi onal marrow cytogenetics.