Types of genes linked to cancer
Many of the genes that contribute to the development of cancer fall into broad categories:
Tumor suppressor genes are protective genes. Normally, they limit cell growth by monitoring how quickly cells divide into new cells, repairing mismatched DNA, and controlling when a cell dies. When a tumor suppressor gene is mutated, cells grow uncontrollably and may eventually form a mass called a tumor. BRCA1, BRCA2, and p53 are examples of tumor suppressor genes. Germline mutations in BRCA1 or BRCA2 genes increase a woman’s risk of developing hereditary breast or ovarian cancers. The most commonly mutated gene in people who have cancer is p53. In fact, more than 50% of all cancers involve a missing or damaged p53 gene. Most p53 gene mutations are acquired mutations. Germline p53 mutations are rare.
Oncogenes turn a healthy cell into a cancerous cell. Mutations in these genes are not inherited. Two common oncogenes are:
HER2, which is a specialized protein that controls cancer growth and spread, and it is found on some cancer cells, such as breast and ovarian cancer cells
The ras family of genes, which make proteins involved in cell communication pathways, cell growth, and cell death.
DNA repair genes fix mistakes made when DNA is copied. But if a person has an error in a DNA repair gene, these mistakes are not corrected. And then they become mutations, which may eventually lead to cancer. This is especially true if the mutation occurs in a tumor suppressor gene or oncogene. Mutations in DNA repair genes can be inherited, such as with Lynch syndrome, or acquired.