Transcript Fragile Sites and Cancer Powerpoint

The Link Between
Fragile Sites and
Cancer
Susan Chabot
2015-2016
Honors Genetics
Unstable Chromosome Regions/
Fragile Sites
• First identified in 1970.
• Staining of metaphase chromosomes, one area failed to
stain giving the appearance of a gap.
• Gaps were susceptible to chromosome breakage.
• Cause of fragility is unknown.
• 120 fragile sites have been identified to date.
• Considered part of normal chromosome structure
and present in nearly all individuals.
FHIT Gene
• FHIT gene (fragile histidine triad) located within FRA3B on p arm of
chromosome 3.
• FHIT gene acts in tumor suppressor function.
• The normal protein product of this gene is absent in cells of many
cancers
• Lung
• Esophagus
• Breast
• Cervical
• Liver
• Kidney
• Pancreas
• Colon
• Stomach
WWOX Gene
• Acts as a tumor suppressor gene, provides surveillance by
recognizing cancer cells and causing apoptosis.
• Located in FRA16D site on chromosome 16.
• Implicated in a range of human cancers/Found to be lost
or silenced in variety of cancers:
• Lung, breast, ovary, prostate, bladder, esophagus, pancreas
• If gene is present, it is heavily methylated and inactive.
Inducers and Enhancers of Fragile Sites