The Significance of Circulating Biomarkers in Gastric Cancer

Overview of Gastric CA

Gastric cancer, also referred to as stomach cancer, is a common cancer that occurs worldwide. It frequently affects men above 50 years old with higher incidence in certain countries, including Iceland, Chile and Japan. Most cases of gastric cancer are diagnosed late as symptoms of the disease are often non-specific during the early stage. These symptoms include heartburn, sensation of fullness and bloating. Advance gastric cancer usually manifest with abdominal pain, sudden weight loss, nausea, vomiting blood, frequent fatigue and other vague abdominal symptoms. Most patients also complain of getting easily full after eating little food.

The risk factors for the development of gastric cancer includes history of cancer in the family, H. pylori infection, smoking, athropic gastritis and gastric polyp. Majority of this cancer develops due to H. pylori infection which can be eradicated by the use of antibiotics.

Circulating Biomarkers

There are several substances in the blood which can help detect the presence of cancer. These substances are called biomarkers or tumor markers. When something is wrong with certain organs in the body, they produce specific biomarkers, and the increase in their value usually indicates disease. Biomarkers are often used for screening purposes as well as for monitoring the response of patients to cancer treatment. The test is performed by extracting a small amount of blood in the vein to be sent to the laboratory for the measurement of the levels of certain biomarkers in the blood.

The following are the circulating biomarkers frequently used in the screening, diagnosis and prognostication of gastric cancer patients.

CEA or Carcinoembryonic Antigen

CEA is present during the development of the fetus, stops at birth, and is normally present in the blood in very low levels. Individuals with cancer usually have elevated CEA measurement in the blood. This biomarker is especially used for monitoring the response of colon cancer patients to their treatment. It is however, not specific to colon cancer alone. CEA is also elevated in cancer of the prostate, stomach, breast, liver and pancreas. It is not generally used in screening the population for cancer, but physicians may request for it when they suspect cancer in some patients. But an increase in CEA does not always mean cancer as it can also become elevated in diseases like emphysema, ulcerative colitis, rectal polyps and peptic ulcer.

CA 19-9

CA 19-9 is used to diagnose cancer in the pancreas and is likewise elevated in gastrointestinal and liver cancer.

CA 72-4

CA 72-4 demonstrates good specificity in detecting gastric cancer.

CA 125

CA 125 is an important marker for cancer in the ovary. Increased levels of CA 125 is also present in non-ovarian cancers, such as cancer of the lungs, breast and stomach.

References

PubMed Central: Biomarker Insights

Lab Tests Online: CEA

Medline Plus: Gastric Cancer

Cancer Center: Tumor Markers