Abstract
The purpose of this study was to investigate the correlation of flow cytometric (FCM)
DNA content and cell cycle characteristics of Barrett's Esophagus (BE) with age and
sex of the patients, length, histologic type and dysplasia of BE. Forty-one patients
affected by histologically confirmed BE had multiple biopsies taken from the metaplastic
epithelium and one biopsy taken from the gastric fundus, as control. The samples were
either stored at -80° C or immediately measured. Nuclei suspensions were obtained,
stained with DAPI, measured with a high resolution flow cytometer (ICP22A, Ortho Instruments)
and analyzed for the evaluation of the relative DNA content and the S- and G2+M phases
of the cell cycle. DNA histograms having two distinct G0/G1 peaks were classified
as DNA aneuploid. The degree of DNA aneuploidy (DNA Index, DI), defined as the ratio
of abnormal to normal DNA content, was obtained from the mixture of each BE sample
with its control sample and trout erytrocytes.
We found six patients with DNA aneuploid populations (14.6 %), whose DNA Index values
were 1.05 (in two), 1.8 (in one), and 2.0 (in three cases). DNA ploidy did not correlate
with age and sex of the patients, length, histologic type, and dysplasia of BE. Among
the 13 patients with dysplasia (6 indefinite, 4 low grade and 2 high grade with intramucous
adenonocarcinoma) only two (one indefinite and one low grade) showed DNA aneuploidy
(15.4 %). In addition, we found that the S-phase and the G2+M-phase fractions in BE
samples were both significantly higher than those of the controls (respectively, p = 0.01
and p = 0.0008).
We suggest that near-diploidy and tetraploidy in BE are indicative of an early genomic
instability which may lead to a more abnormal DNA content. This expected DNA ploidy
evolution would be in agreement with a recent model obtained from the analysis of
a large number of preneoplastic and neoplastic lesions of the colon-rectum (1).
