Fluorescence in situ hybridization to evaluate dysplasia in Barrett's esophagus: a pilot study.

Background: Histological disagreement is frequent in the diagnosis and grading of dysplasia in Barrett's esophagus (BE).

Aims: To identify selective markers for dysplasia in BE and to improve the differentiation between low-grade dysplasia (LGD) and high-grade dysplasia (HGD).

Methods: Eight BE esophageal mucosectomies (7 males) were analyzed by conventional histology and immunohistochemistry for p53 and Fluorescence In situ Hybridization (FISH) for chromosomes X, Y, 4, 8, 17, 18. The female mucosectomy was considered as a control for the XY probe.

Results: p53 confirmed multifocal dysplasia in all cases. All patients displayed increased aneusomy for chromosomes 4, 8, 17 and 18 along the sequence of cancer progression. There was also a trend for chromosome 8 to be below the FISH cutoff; 50% of cases showed aneusomy for chromosome 18 in areas with differing grades of dysplasia. Aneusomy was increased for chromosomes 4 and 17, to a similar extent in LGD and HGD. In male specimens, the presence of chromosome Y was revealed in Barrett's mucosa and LGD, but not in HGD and intramucosal carcinoma.

Conclusions: FISH in BE may be useful diagnostic to confirm the diagnosis of HGD. Loss of chromosome Y might be a selective marker of HGD in male patients.