DNA flow cytometry shows promise in diagnosing Barrett's esophagus dysplasia

Last Updated: 2017-08-03

By David Douglas

NEW YORK (Reuters Health) - Flow cytometric analysis of DNA content using formalin-fixed paraffin-embedded (FFPE) samples, rather than fresh tissue samples, from patients with Barrett's esophagus can help in dysplasia diagnosis and risk stratification, according to researchers.

Dr. Won-Tak Choi, lead author of a new study of the approach, told Reuters Health by email, "Given that the diagnosis of high-grade dysplasia (HGD) in patients with Barrett's esophagus usually prompts resection or endoscopic ablative therapy, DNA flow cytometry can be selectively performed on borderline HGD cases (where a definite diagnosis of HGD is difficult based on histology) to confirm a morphological impression or suspicion of HGD, and in situations where there is discordant interpretation among expert gastrointestinal pathologists before initiating aggressive clinical management."

Dr. Choi, of the University of California at San Francisco Medical Center, further noted that "DNA flow cytometry can also be performed on low-grade dysplasia (LGD) and indefinite for dysplasia (IND) samples to identify a subset of patients who may be at increased risk for subsequent detection of HGD or esophageal adenocarcinoma and may benefit from more frequent endoscopic surveillance or ablative therapy."

In the study, published in Gut, online July 25, Dr. Choi and colleagues performed DNA flow cytometry on FFPE samples: 80 HGD, 38 LGD, 21 IND, and 14 negative for dysplasia.

DNA content abnormality was identified in 95.0% of the HGD samples, 21.1% of the LGD samples, 9.5% of the IND samples, and none of the negative samples. For HGD, the estimated sensitivity was 95% and the corresponding specificity was 85%.

The researchers note that the presence of DNA content abnormality correlated with increasing levels of dysplasia. And in patients with baseline LGD or IND, by univariate analysis the hazard ratio for subsequent detection of HGD was 7.0; for esophageal adenocarcinoma, it was 20.0.

The investigators note that, in addition to being relatively simple and inexpensive, using FFPE tissue for DNA flow cytometric analysis has the advantage of allowing for selective application to test areas that are morphologically abnormal. It also avoids obtaining separate biopsies for flow cytometry and histology, simplifies handling (compared with handling fresh tissue), and permits direct histology-flow cytometry correlation.

The researchers call for further studies but conclude that, in patients with Barrett's esophagus, "our findings support the use of DNA flow cytometry from FFPE tissue."

SOURCE: http://bit.ly/2vszGWM

Gut 2017.