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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A141
Measurement of total nuclear DNA content ("ploidy") is a widely-used
quantitative pathology procedure. However one of the major problems in the
field has been the wide variation in results reported in the literature.
A multi- laboratory experiment was therefore carried out to study the effects
of a) cell selection, and b) sample size on ploidy parameters. Seven
Feulgen-stained breast imprint specimens were circulated between three
different laboratories whose personnel are experienced in ploidy measurement.
From each Laboratory, two sets of ploidy measurements were obtained for
each specimen: a) from their own selection of cells, made according to their
usual measurement protocols, and b) from a "central" selection of cells, which
are relocated using the AxioHOME computerised microscope or other similar
equipment. All results were processed using the EUROQUANT remote ploidy
analysis system via the world wide web. The whole experiment was managed
by means of a web site which distributed aims, experimental protocols,
current status, data and results. Although broadly similar
histogram patterns were obtained by all laboratories for all specimens,
numerical results for two major parameters (DNA Index and S-Phase fraction)
showed substantial differences. Also very large variations were occasionally
found. The major source of variation was found to be the selection of
internal reference cells; the selection of tumour cells had a relatively
minor effect. DNA Index figures usually stabilise after relatively small
samples, but large sample sizes are required for accurate S-phase Fraction
measurements.
PLOIDYVAR - INVESTIGATING VARIABILITY IN PLOIDY PARAMETERS
Tucker J *, Haroske G +, Giroud F ++, Sowter C **
* Pathology Dept., Edinburgh University,
** Dept. Pathology, St. Bartholomew's Hospital, London, UK ,
+ Inst. Pathology, University of Technology, Dresden, Germany,
++ Inst. Albert Bonniot, Université Joseph Fourier, Grenoble, France