Cancer is a Genetic Disease Flashcards
When do somatic mutations occur
after conception
Somatic mutations can occur anywhere but?
germ cells
Where are germline mutations present?
in every cell of the body
Causes of mutations in cancer
normal cell division/DNA replication
exposure to carcinogens
increasing genomic instability
somatic recombination
epigenetic gene silencing
inception of retroviral oncogenes
Passenger mutations
most mutations are not recurrent among similar types of cancer and likely arose as the cancer developed
driver mutations
other mutation are commonly found in different types of cancer and likely drove progression of the tumor
Two broad classes of Driver mutations
oncogenes & tumor supressor genes
What is an oncogene?
control the normal growth and survival of cells
(cell cycle regulation, cellular signal pathways (most common), DNA repair)
What do mutations in proto-oncogenes cause
excessive levels of activity
What is a proto-oncogene
normal version of oncogene
How many mutations are needed for activation of proton-oncogene
single mutation on one allele
How many proto-oncogenes have been identified in humans
50
Growth factor oncogene
INT-1, SIS
Growth Factor receptor oncogene
HER2/NEU, RET, MET, & ERBB-1
Nonreceptor tyrosine kinases oncogenes
SRC & ABL
Signal Transducer Oncogenes
RAS
Cell cycle regulators oncogenes
CDK2 & CDKN1A
Nuclear transcription factor oncogenes
N-MYC, JUN, FOS
Signal transduction pathways transmit extracellular and intracellular signals to regulate cell functions such as:
growth, apoptosis, proliferation, cell-cell adhesion, senescence
MAPK Pathway
Mitogen-activated protein kinase
regulates cell growth, proliferation, differentiation, and death
What do tumor suppressor gene do?
most negatively regulate cell growth or maintain genome integrity
Driver mutations in tumor suppressor genes are __ of function
loss of function
Typically require inactivating mutations at both alleles
tumor supressor genes
Many inherited conditions are due to inherited mutations in
tumor supressor genes