Types of genes that are mutated in cancer:
One kind is called oncogene. Everybody has proto-oncogenes; they normally stimulate cell growth. They’re what you need to grow and live. But if a proto-oncogene becomes mutated, it can be activated all the time. This causes the cell to grow out of control. A proto-oncogene with a gain of function mutation is called an oncogene. It makes the cell continue to grow whereas normally, without the mutation, the cell would stop growing because it is being controlled properly.
Tumor suppressor genes lead to the production of proteins that help regulate cell division. A tumor suppressor gene normally keeps the cell from dividing too quickly. When tumor suppressor genes do not work properly, cells can grow out of control, which can lead to cancer. It’s only when several of the genes become mutated and don’t work properly, that the cell becomes a metastatic cancer.
Justification: BRCA1, BRCA2, and p53 are examples of tumor suppressor genes. All people have two copies of the genes BRCA1 and BRCA2, and both men and women can pass down mutations in these genes. If you have a parent with a BRCA1 or BRCA2 mutation, there is a chance you inherited either the mutated (nonworking) BRCA gene or the working BRCA gene from this parent.You have a 50 percent chance of inheriting the nonworking BRCA gene, which would cause you to have an increased risk for cancer. There is also a 50 percent chance that you inherited a working BRCA gene, in which you have the same risk for cancer as a person in the general population.
A third gene which may cause tumors when mutated are DNA repair genes, also know as DNA polymerases. DNA repair genes code for proteins whose normal function is to correct errors that arise when cells duplicate their DNA before cell division.Mutations in DNA repair genes can lead to a failure in repair, which in turn allows subsequent mutations to accumulate. Certain forms of hereditary colon cancer involve defects in DNA repair.
Types of mutations:
A change in DNA sequence will result in a change in the RNA sequence and may have an impact on the amino acid sequence of a protein.
Insertions- add one or more nucleotides to the DNA sequence (AAGA ---> AAGAAA)
Deletions- Remove one or more nucleotides from the DNA sequence (OGAT ---> GAT)
Both insertions and deletions can result in a frame shift (a shift in the reading frame, the groupings of codons change)