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 | | | Animations | | |
 | | How a Proto-oncogene Becomes an Oncogene
A depiction of some types of mutations that can occur to turn a proto-oncogene into an oncogene.
View Quicktime Movie | |  | | p53's Role in the Cell
Shows various roles that p53 plays in the cell to protect the genome of the organism.
View Quicktime Movie | |  | | Telomeres
Shows the concept of how the ends of chromosomes, the telomeres, shorten each time the cell divides.
View Quicktime Movie | |  | | The Cell Cycle: Cyclins and Checkpoints
A depiction of the cell cycle and role that cyclins play in the process; this animation also shows the role of checkpoints in regulating the cell cycle.
View Quicktime Movie | |  | | The Signal Transduction Pathway
A depiction of the signal transduction pathway that is involved with the growth process of the cell.
View Quicktime Movie | |
| Images | | |
 | | Telomeres
Human chromosomes with the telomere tips stained. The telomeres are protective ends of the chromosomes that get shorter each time a chromosome is replicated. | |  | | Harold Bishop and Harold Varmus
Michael Bishop, PhD, and Harold Varmus, PhD. They received the Nobel Prize in 1989 for their discovery that normal cells contain genes capable of becoming cancer genes. | |  | | Ras protein
The model structure of the proto-oncogene ras. Ras plays an important role in the signal transduction pathway that is involved with cell growth. Mutations in ras have been implicated in many cancers. | |  | | Breast cancer cells
A micrograph of breast cancer cells | |  | | Signal transduction pathway
A signal (in this example, a growth factor) binds to a tyrosine kinase receptor on the outside of the cell. This activates the membrane protein (through the addition of phosphate groups), which in turn activates proteins in the cytoplasm such as kinases. Several other proteins may be involved in the cascade, ultimately activating one or more transcription factors. The activated transcription factors enter the nucleus, where they stimulate the expression of the genes that are under the control of that factor. This is an example of the RAS pathway, which results in cell division. | |  | | The cell cycle
The cell cycle is an ordered process of events that occurs in four stages. During the two gap phases, G1 and G2, the cell is actively metabolizing but not dividing. In S (synthesis) phase, the chromosomes duplicate as a result of DNA replication. During the M (mitosis) phase the chromosomes separate in the nucleus and the division of the cytoplasm (cytokinesis) occurs. There are checkpoints in the cycle at the end of G1 and G2 that can prevent the cell form entering the S or M phases of the cycle. Cells that are not in the process of dividing are in the G0 stage, which includes most adult cells. | |  | | Some genes associated with cancer
| |  | | Some drugs used in the treatment of cancer
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