Dual colour FISH in paraffin wax embedded bone trephines for identification of numerical and structural chromosomal abnormalities in acute myeloid leukaemia and myelodysplasia.
OBJECTIVE
The advent of new treatments for haematological malignancies has led to the need for a correlation between cytogenetic and morphological abnormalities. This study aimed to achieve this by the application of interphase cytogenetics to marrow trephine sections, a technique not previously reported for formalin fixed, paraffin wax embedded trephine biopsies.


METHODS
Dual colour fluorescence in situ hybridisation (FISH) was used to detect numerical and structural abnormalities in routinely processed paraffin wax embedded trephine biopsies. Three cases with t(8;21) and three with t(15;17) were analysed, together with a case of trisomy 8. Chromosome specific probes were hybridised with sections and disclosed by fluorescein isothiocyanate and rhodamine/Texas red labelled antidigoxigenin and antibiotin amplification; translocations were identified by colocalisation of probes using a double wavelength bypass filter.


RESULTS
A translocation signal was present in 12% and 11.5% of the cells counted in the t(8;21) and t(15;17) cases, respectively, but in none of the normal controls (p < 0.001). In the case of trisomy 8, 9% of the cells counted contained three hybridisation signals for chromosome 8, whereas no cell contained more than two in the normal control (p < 0.001).


CONCLUSIONS
This technique is useful for archived routinely processed material, enabling it to be used as a research tool but also, and perhaps more importantly, in clinical practice.
Le Maitre
C L
CL
Laboratory of Medicine, Department of Medicine, University of Manchester, Manchester M13 9PT, UK.
Byers
R J
RJ
Liu Yin
J A
JA
Hoyland
J A
JA
Freemont
A J
AJ
D000208:Acute Disease; D000328:Adult; D001706:Biopsy; D001853:Bone Marrow / Q000473:pathology*; D002869:Chromosome Aberrations; D002898:Chromosomes, Human, Pair 8; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007951:Leukemia, Myeloid / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D016612:Paraffin Embedding; D014178:Translocation, Genetic; D014314:Trisomy