What Are The Causes of Stomach Cancer?

Stomach (Gastric) cancer occurs when abnormal cells within the stomach grow out of control. Some risk factors can increase your chances of developing gastric cancer. But have you ever wondered what makes the normal, healthy cells in your stomach lining turn cancerous? Let’s take a deep dive into what causes gastric cancer at a molecular level.

Cancer is caused by mutations (changes) in your DNA. Your DNA carries thousands of genes. These genes provide instructions, telling your cells how to grow, develop and function. They produce different types of proteins involved in a wide range of cellular processes.

Cancer is caused by mutations in one or more genes within your cells. In the case of gastric cancer, these mutations occur in the genes of your stomach cells. As a result, the mutated genes produce faulty proteins that can no longer regulate processes like cell growth and cell death.

Having a single gene mutation is unlikely to cause cancer. This is because our cells have various mechanisms in place to repair DNA damage or mutations. However, when multiple mutations accumulate and different cellular processes go haywire, your cells can grow and divide abnormally. This causes tumors to form, which turn malignant when they are capable of invading other tissues and organs.

Mutations in certain genes, like tumor suppressor genes, oncogenes and DNA repair genes, contribute strongly to cancer formation.

Tumor suppressor genes

Tumor suppressor genes regulate genes involved in cell division and cell death. This ensures cells do not multiply too quickly.

Gene regulation is the process by which a cell controls the timing, location, and amount of gene expression. It usually involves turning genes on and off. A mutation in a tumor suppressor gene could turn the gene off. This would allow cells to grow and divide unchecked, leading to tumor formation.

The p53 gene, which is faulty in over half of all cancers, is the most commonly mutated tumor suppressor gene in people with cancer. This infamous gene provides instructions to produce the p53 protein, which is responsible for keeping cell division under control. Therefore, when a mutation occurs in the gene, it causes the p53 protein to lose its tumor-suppressing function.

Oncogenes

Proto-oncogenes are genes that normally regulate processes, like cell division and cell death. This is important to maintain healthy tissues and organs in your body. A mutation in a proto-oncogene can permanently activate the gene when it shouldn't be. This turns the proto-oncogene into a malfunctioning gene called an oncogene.

When an oncogene becomes active, cell division and cell death are no longer kept in control. This allows the cells to grow and divide abnormally, thereby leading to cancer formation.

DNA repair genes

The protein products of DNA repair genes are responsible for catching and correcting mistakes that happen during cell division. If they are unable to fix these mistakes, they trigger cell death to ensure that the mistakes do not cause further problems.

Mutations in your DNA repair genes cause their protein products lose their repairing function. The cell fails to correct mistakes in the DNA, allowing them to accumulate. This allows more mutations to build up inside the cell, affecting other genes and cellular processes. Eventually, the cells in your body turn cancerous and cancer starts forming.