Cancer Biology I - Chapter 6: Oncogenes

Practice flashcards covering the definitions, mechanisms of activation, history, and specific examples of oncogenes in human cancer based on the lecture material.

Proto-oncogenes

Normal cellular genes usually involved in cell growth and/or cell division that can become oncogenes due to mutations or increased expression.

Oncogenes

Activated versions of proto-oncogenes resulting from mutation or overexpression, leading to a dominant gain-of-function phenotype like accelerated cell division.

Point mutation

A mechanism of oncogene activation where a change in a single gene (e.g., RAS) results in an abnormal oncoprotein with enhanced stability or activity.

Gene amplification

An increase in the number of copies of a gene, leading to the overproduction of a normal protein.

Chromosomal translocation

A rearrangement where a gene, such as c-MYC, is moved to a region of vigorous transcription, a common cause of Burkitt's lymphoma.

Insertional mutagenesis

The integration of a viral genome near a proto-oncogene, leading to its activation or altered expression.

Promoter/enhancer hijacking

A mechanism where a proto-oncogene is moved near strong regulatory elements, leading to increased protein expression.

Burkitt's lymphoma

A cancer where the proto-oncogene c-MYC on chromosome 8 is translocated to chromosome 14, 2, or 22, placing it near immunoglobulin loci.

PML-RARα

A transforming protein of acute promyelocytic leukemias generated by the fusion of the promyelocytic leukemia protein to the retinoic acid receptor-alpha.

Michael Bishop and Harold Varmus

Winners of the 1989 Nobel Prize for their discovery of the cellular origin of retroviral oncogenes (c-SRC).

Rous Sarcoma Virus (RSV)

An animal virus discovered by Peyton Rous that captures the c-src gene and carries the mutated v-src oncogene, causing tumors in poultry.

c-SRC

A proto-oncogene naturally present in healthy vertebrate cells that encodes a tyrosine kinase involved in regulating normal cell growth.

v-SRC

A viral oncogene carried by RSV that is a constitutively active, mutated, or unregulated version of the cellular c-src gene.

RAS

A signal transduction oncogene (GTP binding/GTPase) often activated by point mutations in colon and pancreatic cancers.

Transcription factors

One of the five functional classes of oncogenes; includes MYC, JUN, and FOS.

PDGF (SIS)

A growth factor oncogene associated with brain tumors and overexpressed in Simian sarcoma.

EGFR (erbB)

A growth factor receptor oncogene often activated by amplification or rearrangement in brain, breast, and lung cancers.

Cyclin D1 and CDK4

Cell cycle regulators that act as oncogenes when overexpressed or amplified, common in breast and esophageal cancers.

Human Tumor Viruses

Infectious agents linked to at least $15\%$ of all malignant tumors in humans, second only to tobacco smoking as a risk factor.