Cancer Biology Chapter 9 Oncogenes

Origin of Oncogenes

They often come from the insertion of a viral oncogene into affected cells (e.g., the Myc oncogene).

Conversion to Oncogene

The activation of normal proto-oncogenes into oncogenes through mechanisms like mutation, gene amplification, chromosomal translocation, or DNA rearrangement.

Gene Amplification Impact

Increased gene amplification leads to increased cancer risk and decreased survival rates.

Chromosomal Translocation

A process where a piece of one chromosome is broken off and moved to another chromosome.

Philadelphia Chromosome (Fusion Protein)

A specific chromosomal translocation (involving chromosomes 9 and 22) that results in an exchanged segment and a fusion protein.

DNA Rearrangements

Structural changes to DNA including Deletion, Insertion, Transposition, and Inversion.

Methylation

The addition of a methyl group (CH3) to CG islands on genes, which leads to the inactivation (silencing) of that DNA region.

Acetylation

The addition of an acetyl group (CH3-C=O) which loosens the DNA, leading to increased gene expression.