DNA CONTENT-ANALYSIS OF BARRETTS-ESOPHAGUS BY FLOW-CYTOMETRY

The purpose of this study was to investigate the correlation of flow c ytometric (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 histologicall y confirmed BE had multiple biopsies taken from the metaplastic epithe lium and one biopsy taken from the gastric fundus, as control. The sam ples were either stored at -80''C or immediately measured. Nuclei susp ensions were obtained, stained with DAPI, measured with a high resolut ion now cytometer (ICP22A, Ortho Instruments) and analyzed for the eva luation 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 classi fied as DNA aneuploid. The degree of DNA aneuploidy (DNA Index, DI), d efined as the ratio of abnormal to normal DNA content, was obtained fr om the mixture of each BE sample with its control sample and trout ery trocytes. 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 (i n three cases). DNA ploidy did not correlate with age and sex of the p atients, length, histologic type, and dysplasia of BE. Among the 13 pa tients with dysplasia (6 indefinite, 4 low grade and 2 high grade with intramucous adenonocarcinoma) only two (one indefinite and one low gr ade) showed DNA aneuploidy (15.4 %). In addition, we found that the S- phase and the G2+M-phase fractions in BE samples mere both significant ly higher than those of the controls (respectively, p=0.01 and p=0.000 8). 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 wit h a recent model obtained from the analysis of a large number of prene oplastic and neoplastic lesions of the colon-rectum (I).