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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A116
The aim was to investigate a method for simultaneous measurement of
cytokeratin and DNA content in colorectal cancer, in order to improve the
estimation of the S-phase fraction (SPF) of DNA aneuploid subpopulations.
From 162 colorectal tumors fine-needle aspirates of 744 frozen biopsies were
analyzed. Cytokeratin/DNA measurements were based on staining in PBS with
0.3% saponin, propidium iodide, RNase, and FITC-conjugated anti-cytokeratin
antibody "(DAKO MNF-116)". Fluorescence was compensated after measurement.
DNA histograms of cytokeratin-positive cells "(CG)" were found by gating of
the cytokeratin/DNA measurement (CT) based on an isotype control. These
results were compared to univariate DNA measurements (Vi) (method of Vindel°v
et al.). For the initial analysis, good quality DNA histograms with low CV,
debris and a sufficient number of counts in the region of interest were
selected, representing 406 biopsies from 129 patients. The median G1 peak
CV was 2.3% for Vi and 3.2% for CG/CT. The SPF was higher in CG than in CT
histograms (mean difference 3.1%, p<0.0001), and higher in CT than in Vi
(1.3%, p=0.0005). The correlation coefficient between SPF for CG and Vi was
0.56 (p<0.0001). Comparison of the DNA ploidy patterns between Vi and CT,
including only a DNA subpopulation if the G1 fraction was 10% or more of
the region of interest, showed complete accordance both ways in 346 (85%)
biopsies. We conclude that this method yields the same ploidy pattern as
Vi and that SPF is significantly different for CG, suggesting that additional
information may be obtained using this measure.
BIVARIATE ANALYSIS OF CYTOKERATIN AND DNA IN COLORECTAL CANCER BY
FLOW CYTOMETRY ON FINE-NEEDLE ASPIRATES FROM FROZEN TISSUE
Post C, Christensen IJ, Flyger H *, Christiansen J, Larsen JK
Finsen Laboratory, Rigshospitalet, Copenhagen, * Dept. of Surgery,
Hillerod Hospital, Denmark