| Type |
Definition |
Relation to Cancer |
| Point Mutation |
the change, insertion, or deletion of a single base in DNA |
the mutation can make a proto-oncogene, the normal form
of a potentially cancer causing gene, into an oncogene, a cancer causing gene, usually making the Ras
oncogene |
| DNA Rearrangement |
In the lymphatic system, DNA on chromosome 6 naturally rearranges to form different white blood cell types. |
This can make an oncogene, or inappropriately move one next to a promoter |
| Gene Amplification |
repeats of segments of proto-oncogenes, or even whole proto-oncogenes, occur in the DNA |
too much of "bad" protein is produced resulting in too much growth and/or cell division |
| Transcription Factors |
proteins that control gene expression |
when the genes that code for transcription factors are muted, genes are expressed that shouldn't be and it can activate the proteins which signal the beginning of mitosis |
| Fusion Proteins |
a proto-oncogene is moved next to another gene by translocation |
an oncogene is formed and expressed |
| Viral Oncogenes |
a portion of viral dna that incorperates itself into the human genome, and can put gene expression under viral control because of strong promoters in the viral DNA |
the viral oncogene results in abnormal cell division or the expression of a human oncogene next to the viral promoters |
| Inability to Repair Damaged DNA |
tumor supressor genes such as p53 and other repair mechanisms don't work |
mutations that result are not fixed, the cell is allowed to reproduce, and the mistakes propagate, resulting in abnormal cells and eventually cancer |
