TCGA's Study of Esophageal Cancer
What is esophageal cancer?
TCGA studied the two most common types of esophageal cancer: squamous cell, which arises in the flat cells lining the esophagus, and adenocarcinoma, which arises in the cells that release mucus and other fluids. Esophageal cancer is the 18th most common cancer type, with an estimated 16,980 new cases in 2015, representing 1% of all new cancer cases in the United States.1
Esophageal cancer is three to four times more common in men than in women and the risk of development is higher with age.2 The two different types of esophageal cancer have with different risk factors. The risk of developing squamous cell esophageal cancer is increased by tobacco smoking and heavy drinking. Adenocarcinoma of the esophagus is associated with the reflux of stomach acid into the esophagus in disorders such as gastroesophageal reflux disease and Barret’s esophagus.
The rates for new esophageal cancers in the United States has been falling by an average of 1.2% each year over the last 10 years. However, esophageal cancer tends to be diagnosed at an advanced stage because it is often undetected until major symptoms appear, leading to a low 5 year survival rate of 29.3% between 2005 and 2011. Esophageal cancer is treated with a combination of therapies that may include surgery, radiation, chemotherapy, targeted therapy, or endoscopic treatments. Additional information on esophageal cancer.
What have TCGA researchers learned about esophageal cancer?
- Significant molecular differences between esophageal adenocarcinoma and esophageal squamous cell carcinoma may help improve how they are classified:
- Esophageal squamous cell carcinomas share more genetic features with head and neck squamous cell carcinomas than with esophageal adenocarcinomas and may therefore benefit from similar therapeutic approaches to head and neck squamous cell carcinomas.
- Adenocarcinomas contain molecular changes similar to the chromosomal instability (CIN) subtype of stomach cancer. This suggests clinical trials of esophageal adenocarcinomas may be improved by grouping them with CIN stomach cancers.
- Genomic alterations may represent effective targets for therapy:
- Frequent alterations of genes that regulate the cell cycle may be treated with existing drugs.
- One third of esophageal adenocarcinomas studied harbored an alteration to the ERBB2 gene, which encodes the HER2 protein, and may be targeted with HER2 inhibitors.
1Howlader N, Noone AM, Krapcho M, et al., eds. SEER Cancer Statistics Review, 1975-2012, National Cancer Institute. Bethesda, MD, https://seer.cancer.gov/csr/1975_2012/, based on November 2014 SEER data submission, posted to the SEER web site, April 2015.
2American Cancer Society. Cancer Facts and Figures 2015. Atlanta: American Cancer Society, Inc. 2015.