Is pish more effective than cytogenetics in detecting chromosome 5 abnormalities in mds/anll?

Eighteen patients with Myelodysplastic Syndrome (MDS) ( 6 RA, 3 RAEB and 9 RAEB-t ) and B with Acute Non-Lymhocytic Leukemia were submitted to cytogenetic analyses and to fluorescence in situ hybridization (FISH) with a 5q31-specific DNA probe and with a painting probe for chromosme 5. Both the technique were applyed on bone marrow samples FISH was performed only on metaphase cells.By this way the in situ assay has a sensitivity of 100%. Conventional cytogenêtics detected interstitial long arm deletion of chromosome 5 in eleven cases(3 RA, 3 RAEB and 5 AN1.L) In six of them (3 RA and 3RAEB) FISH showed only one signal corresponding to band 5q31. In all these six cases cytogenêtics defined the deletion as del(5)(ql3q31) In the remaining five cases, all ANLLs evolved from MDS and all without a good prognosis translocation, chromosome 5 long arm was involved in balanced and unbalanced translocations, that needed a painting probe for this chromosome to be used. By this way it was showed that four of these five cases retained band 5q31, that remained on the rearranged chromosome 5 (u\o patients) or on the other translocated chromosomes (two patients). All these patients were submitted to standard chemotherapy protocols, but none of them achieved a response In conclusion our preliminary results show a good agreement between cytogenêtics and FISH in detecting 5q31 deletion and indicate that the two technique provide complementary information when analyzing chromosome 5 long arm rearrangements.