SNP Shot: Genomic Insights

Hereditary diffuse gastric cancer (HDGC) is a genetic condition that significantly elevates the risk of developing a specific type of stomach cancer. This type, called diffuse gastric cancer, doesn't form a distinct tumor. Instead, cancerous cells proliferate beneath the stomach lining, causing it to thicken and stiffen. This cancer is invasive, meaning the malignant cells are prone to spreading (metastasizing) to other parts of the body, like the liver or nearby bones.

Diffuse gastric cancer symptoms often appear in the later stages of the disease and can include stomach pain, nausea, vomiting, difficulty swallowing (dysphagia), loss of appetite, and weight loss. If the cancer spreads to other tissues, it can cause an enlarged liver, yellowing of the skin and eyes (jaundice), fluid buildup in the abdomen (ascites), firm nodules under the skin, or bone fractures.

In individuals with HDGC, gastric cancer typically manifests in their late 30s or early 40s, although it can occur at any point in adulthood. Early detection of diffuse gastric cancer offers a favorable survival rate. However, due to its hidden growth beneath the stomach lining, it is often diagnosed only after it has become extensively invasive. At this advanced stage, the survival rate is around 20 percent.

Individuals with HDGC may also have a higher risk of developing other cancers, including lobular breast cancer (a type originating in the breast's milk-producing glands), prostate cancer, and colorectal cancer (cancers of the colon and rectum). Most individuals with HDGC have a family history of HDGC-related cancers. In some families, all affected members have diffuse gastric cancer, while in others, some have diffuse gastric cancer and others have other related cancers, such as lobular breast cancer. Cancers linked to HDGC often develop before age 50.

Inheritance:

HDGC follows an autosomal dominant inheritance pattern. This means that inheriting just one copy of a mutated CDH1 gene in each cell is enough to increase the likelihood of developing cancer. Typically, an affected individual has one parent who also has the condition.