Cancer of Genetics Flashcards
define clonal
tumor that originated from common ancestral cell that accumulated numerous specific mutations
what are characteristic of many types of cancers?
reciprocal chromosomal translocations
what type of mutations give a growth advantage to tumor cells?
driver mutations
what type of mutations have no direct contribution to cancer phenotype?
passenger mutations
cancer stem cell hypothesis predicts that
every cell in a tumor has the potential to form a new tumor
what indicates that cancer develops from accumulation of several mutagenic events in a single cell?
age-related incidence with cancer
carcinogens are
cancer-causing agents
tumorigenesis is the
development of a malignant tumor
genomic instability of cancer cells is characterized by
somatic point mutations
chromosomal effects
list some examples of chromosomal effects
translocation, aneuploidy, DNA amplification. deletions
epigenetics is the study of
heritable changes in gene expression that DO NOT alter DNA sequences
what are some examples of epigenetic modifications?
- DNA methylation
- histone acetylation and phosphorylation
cancer cells contain altered
DNA methylation patterns, and histone modifications
cells are stimulated to re-enter the cell cycle by the presence of
external growth factors
define signal transduction
process of transmitting growth signals from external environment to cell nucleus
where are the 3 cell cycle checkpoints?
- G1/S
- G2/M
- M
what are the 2 classes of proteins that controls progress through the cell cycle?
kinases
cyclin-dependent kinases
caspases are
proteases responsible for initiating apoptosis and digesting intracellular components
what are the steps in apoptosis?
- nuclear DNA becomes fragmented
- disruption of internal cellular structures
- dissolution of cell into spherical apoptotic bodies
- engulfing of bodies by phagocytic
proto-oncogenes are genes that
stimulate cell growth and division
tumor-repressor genes are genes that
regulate cell cycle checkpoints or initiate apoptosis
proto-oncogenes…
- signal transduction molecules that stimulate cell division
- cell-cycle regulators that move cell through cell cycle
what is an example of a proto-oncogene?
ras gene
ras gene regulates
cell growth and division
when both alleles of a tumor-suppressor gene are inactivated the cells become
tumorigenic
what is the most frequently mutated gene found in 50% of all cancers?
TP53
what percentage of metastatic cells become metastatic tumors?
0.01%
to metastasize from primary tumor cancer cells have to
digest components of the EM and basal lamina
what glycoprotein is responsible for cell to cell adhesion?
E-cadherin
most inherited cancer-susceptibility alleles occur in
tumor-suppressor genes
familial adenomatous polyposis is a
genetic predisposition to cancer
what percentage of human cancers are associated with viruses?
15%
any agent that damages DNA has the potential to be
carcinogenic
