Jv. Frei et Vj. Martinez, DNA FLOW-CYTOMETRY OF FRESH AND PARAFFIN-EMBEDDED TISSUE USING CYTOKERATIN STAINING, Modern pathology, 6(5), 1993, pp. 599-605
DNA flow cytometry measurements were performed using cytokeratin as a
second parameter to identify epithelial cells selectively in fresh and
in archival paraffin samples of normal and adenocarcinoma tissues fro
m breast and colon. Fresh specimens consisted of 22 adenocarcinomas of
breast, 20 adenocarcinomas of colon, 16 control breast samples, and 1
3 control colon samples. Paraffin block specimens consisted of 22 aden
ocarcinomas of breast (the same as fresh samples), 20 adenocarcinomas
of colon (the same as fresh samples), 37 control breast samples and 34
control colon samples. The average proportion of cytokeratin-positive
cells per group ranged from 31 to 55% for fresh samples and from 14 t
o 34% for paraffin samples. For aneuploid cells populations of adenoca
rcinomas, which consist only of epithelial cells, the average percenta
ge of cytokeratin-positive cells ranged from 60 to 72%. The technique
gave satisfactory measurements of ploidy and of cell cycle data in bot
h types of samples. Cell cycle measurements were less accurate than pl
oidy measurements in both types of samples, and multiple sampling will
be required for adequate accuracy. The average S-phase fraction of cy
tokeratin-positive cells ranged from 6 to 15% for fresh specimens and
from 11 to 20% for paraffin samples. Similar data were obtained for th
e proliferative index (G1 + S + G2 + M phases). The coefficients of va
riation were smaller for proliferative index than for S-phase fraction
data, indicating greater accuracy. Paraffin data give higher cycling
cell measurements than corresponding fresh data, so separate standardi
zation of measurements may be required for fresh and for paraffin data
.