How Heartburn Can Turn Into Esophageal Cancer, and a Possible Biomarker

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Smokers are significantly more likely than nonsmokers to have acid reflux. In many Western countries, a popular diet—known for its convenience, availability and, frankly, its lack of nutritional value—is also known to cause acid reflux. Some of the affordable foods and beverages easily accessible to Western consumers include fried food, fast foods, pizza, potato chips (and other processed snacks), high-fat meats (bacon, sausage), cheese, alcohol, soda, energy drinks, and etcetera. Unfortunately, this indulgent type of diet can be accompanied by consequences beyond oily skin and an expanding waistband.

Barrett’s Esophagus

Chronic acid reflux can lead to gastroesophageal reflux disease. Gastroesophageal reflux disease can lead to Barrett’s esophagus (BE). BE is a premalignant condition in which the lining of the esophagus becomes damaged by acid reflux. BE can lead to the onset of a type of cancer called esophageal adenocarcinoma (EAC). Over the past few decades, statistics have revealed that the incidence of EAC in Western populations is increasing.

“Esophageal adenocarcinoma (EAC) is on the rise in western countries with increased incidence and high mortality [1, 2].”

Since the popularity of smoking and a heartburn-inducing diet is likely to persist in the West, the early detection of EAC is critical for improving patient outcomes. If a biomarker could indicate a BE patient’s risk of EAC, then early EAC treatment could curb incidence and mortality rates. However, such a biomarker has yet to be confirmed. On February 14, 2022, researchers from Technische Universität München, Columbia University Irving Medical Center and Universitätsklinikum Freiburg published the research paper, “Telomere shortening accelerates tumor initiation in the L2-IL1B mouse model of Barrett esophagus and emerges as a possible biomarker,” in Oncotarget.

“Here we aimed to provide functional evidence for the hypothesis that telomere shortening can directly contribute to tumor initiation, and thus serve as a potential biomarker for BE cancer risk stratification [22, 24].”

Telomere Shortening and Tumor Initiation

“Shortened telomeres is a common sight in epithelial cancers and has also been described in EAC and its precancerous lesions.”

In this study, researchers investigated the impact of shortened telomeres in a mouse model for Barrett’s esophagus (L2-IL1B). The L2-IL1B mouse model is characterized by inflammation that leads to a Barrett-like metaplasia. The team knocked out the mTERC gene (mTERC−/−), which is the catalytic subunit of telomerase in the L2-IL1B mice. 

After mTERC knockout, the researchers found that the telomeres shortened and the mice displayed signs of DNA damage. The tumor area along the squamocolumnar junction (SCJ) was increased in the second generation of these mice, and histopathological dysplasia (abnormal changes) was also increased. In vitro studies indicated that organoid formation capacity increased in BE tissue from the L2-IL1B mTERC−/− G2 mice.

“In summary, we here demonstrated a functional role of telomere shortening, a well observed property of BE, in promoting early onset esophageal tumor initiation in the L2-IL1B mouse model.”

Additional results of the study found that the telomeres in human BE epithelial cells lining the stomach with or without dysplasia were shorter than in gastric cardia tissue (the junction between the lower esophagus and the stomach). The study also found that differentiated cells that make mucus (goblet cells, which help protect the stomach lining) had longer telomeres than cells actively dividing (and more likely to become cancerous) in the columnar lined BE epithelium. 

“Moreover, besides the importance during early carcinogenesis in the mouse model, shortening of telomeres was specifically decreased in dysplastic columnar-type tissue rather than in differentiated goblet cells in human BE- and LGD tissue samples.”

Conclusion

“Here, we demonstrate that telomere dysfunction aggravates the histological phenotype, extends the tumor area in the inflammation-based L2-IL1B mouse model for BE and acts as a driver for early dysplasia development.”

In summary, these findings suggest that shortened telomeres may play a role in tumor development in a mouse model of BE and are associated with proliferating columnar epithelium in human BE. The study suggests that shortened telomeres should be evaluated further as a possible biomarker for predicting EAC cancer risk in people with BE.

“It is plausible that with our measurements we could emulate this with shortened telomeres being at higher risk of genome instability and lowered cell-to-cell variability marking clonal expansion. However, larger studies are needed to test these hypotheses.”

Click here to read the full research paper published by Oncotarget.

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