BIOL 311 Lecture Notes - Tumor Suppressor Gene, Brca2, Exon
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What is Breast Cancer?
Disease where cells in the breast grow and divide uncontrollably creating a
Common forms include ductal (carry milk to nipple) or lobular (glands that
produce milk) cancer.
Symptoms: lump, discharge, size or shape change, tenderness, dimpling, and
scaliness. (Hard to identify)
BRCA1/BRCA2 genes most strongly associated with the development of
breast cancer. Major contributors to increasing the risk acquiring the disease.
How is Breast Cancer Inherited?
Both hereditary and noninherited (sporatic) cases
Inherited in multiple genes that are linked with breast cancer when
Can be due to mutations in BRCA2 gene in an autosomal dominant pattern.
Not all people who inherit the mutated BRCA2 gene will develop breast
cancer, it only increases the risk of development.
BRCA2 gene facts
Official name: Breast Cancer 2, Early Onset
Tumor suppressor gene that prevents rapid cell growth and division
Other functions to be determined – Possible contributor to regulation of
cytokinesis during cell replication
Discovered by Richard Wooster (1994)
Acrocentric on the long arm of chromosome 13 at position 12.3 (13q12-q13)
27 exons, 26 introns
Exon 11 extremely large with 4932 nucleotides
11,386 base pairs – Contains many nucleotide repeats
Produces 3,418 amino acids
Over 300 possible mutations
Mainly in coding regions and exons, but do occur in non-coding regions and
Frameshift mutations (insertions and deletions) – Examples: Deletions on
nucleotides 196, 211, 440, 681.
Deletions are most common