DNA Ploidy Status and Proliferative Activity as Markers of Malignant Potential in Barrett's Esophagus: Flow Cytometric Study Using Routinely Paraffin‐embedded Tissue

Abstract

Regular endoscopic surveillance is recommended for patients with Barrett's esophagus to detect dysplasia and to diagnose carcinoma while it is in an early and possibly treatable stage. However, there are numerous unknown aspects regarding the natural history of dysplasia in this disease, and there is still a need for more accurate markers of risk of a malignant change. The aim of this study was to investigate the usefulness of DNA flow cytometry in Barrett's esophagus to define subgroups of patients showing similar histologic findings but with a different malignancy potential. Routinely formalin-fixed and paraffin-embedded tissues of 43 patients with Barrett's esophagus were processed for flow cytometric measurements (ploidy, proliferative index) and the results were compared with the histologic evolution observed in these patients. Only in the group of patients with "indefinite" dysplasia did we find statistically significant differences between the samples from patients with and without progression to more severe lesions (mean proliferative index of stable patients: 5.2% versus 8.3% in patients with progression, p = 0.001, Student's t-test). The presence in the flow cytometric analysis of a DNA aneuploid cell line is closely related to the presence of severe histologic alterations (i.e., high-grade dysplasia: p < 0.001, Fisher's exact test). Our results suggest that this procedure is at least capable of distinguishing between a real, although incipient, neoplastic process and morphologic changes of a reactive or reparative type. The increment in the tissue proliferative index could be an indicator of an early genomic instability which, with time, will develop into lesions with a more altered DNA content: aneuploidy.

Is there a case for routine clinical application of ploidy measurements in gastrointestinal tumours?

“…Selected studies which investigated DNA ploidy in Barrett's oesophagus are summarized in Table 4. A number of published papers have demonstrated an association between DNA aneuploidy and dysplasia, 69,74–77 whereas others reported that DNA aneuploidy and histological dysplasia are often discordant 78,79 . All studies, except two, demonstrated DNA aneuploidy in biopsies histologically negative for dysplasia (range 3.6–30% of cases).…”

Diagnosis of Esophagogastric Tumors

“…Several apparent associations between Barretts esophagus and biological markers have been reported. The presence of a DNA aneuploid cell line in the flow-cytometric analysis is closely related to the occurrence of severe histological alterations in Barretts esophagus [31]. Since p53 gene mutation, protein accumulation, and DNA aneuploidy would follow in sequence to allow repair of oxidative DNA damage caused by gastroesophageal reflux [32], it has been suggested that it might be possible to detect these events in routinely processed biopsies.…”

Investigation of Genomic Instability in Paediatric Barrett's Oesophagus Using Laser Microdissection on Paraffin‐embedded Endoscopic Biopsies

“…Thus, the recognition of early and objective alternative risk markers, which are less susceptible to sampling error, will be of relevance in the management of BE patients. Flow-cytometry studies of DNA content of epithelial cells in BE of adult patients suggest that neoplastic progression of this condition is associated with a process of genomic instability (1,(14)(15)(16)(17). Recent research also revealed loss of heterozygosity at 3p21, 5q21, 9p21, and 17p13 present in the Barrett's epithelium adjacent to carcinoma as well as in the Barrett's mucosa in sequential biopsies performed before the diagnosis of adenocarcinoma (18,19).…”