Lecture 18 - Cancer Flashcards
(44 cards)
Mutations can occur
in any cell
Germline
Somatic
Germline mutation
Inherited, passed to next gen
gametes (egg or sperm cells)
eg born errors of metabolism
Somatic mutation
in other cells (except gamete)
not passed on
result in cancer
what mutation can result in cancer?
somatic
How many cells make up human body?
37.2 trillion cells
Human cells
grow, divide, renew
what is Cancer?
collection of related diseases and can start anywhere in body.
Cancer cells
no longer respond to signals that control cellular growth and death.
Over time cells become increasingly resistant to controls that maintain normal tissue — and divide more rapidly.
Despite multiple abnormalities, What do cancer cells evade?
programmed cell death.
In the late stages of cancer, cells…
break through normal tissue boundaries and metastasize
(spread) to new sites in body.
what underlies the development of cancer?
Multiple mutations
Cancer is the result of an accumulation of
mutations.
Most associated with DNA replication.
why does the incidence of cancer greatly increases with age?
The more times a cell divides, more likely it to gain a mutation -
How many genes encode proteins that normally regulate cell growth and division?
Hundred
What can lead to cancer?
Mutations that alter genes that regulate cell growth and division in somatic cells.
Mutations may be
Spontaneous (occur by chance)
Exposure to mutagen (Carcinogen)
what are the 2 types of genes that can cause cancer when mutated?
Tumor suppressor genes
Onco-genes
Car analogy
Car is…
Brake is…
Accelerator is…
cell proliferation/growth
Tumor suppressor genes
Onco-genes
Brake pedal are Tumor suppressor genes
Encode proteins that normally prevent uncontrolled cell growth e.g
• proteins that inhibit cell division
• Prevent other mutations (DNA repair enzymes)
Lack of Tumor suppressor genes
stimulate cell growth
- i.e. recessive mutations promote cancer
Accelerator are Onco-genes
Encode proteins that promote cell growth (cell division)
Cancer mutations increase activity of these genes.
Dominant mutations promote cancer
Tumor suppressor genes
mutations that decrease gene activity cause cancer
Tumor suppressor genes
Signal for cell division results in…
E2F transcription factor
going to nucleus.
Cell division genes can be expressed.
Tumor suppressor genes
What cause activation of the
E2F transcription factor?
Loss of function mutation in RB gene.
AND
Loss of function mutation in p16 gene
