class 18-cancer

hypomethylated

less methylation

hypermethylation

more methylation

how considerable is cancer as a human health issue

it affects 1 out of 3 people

how common is cancer in western countries

its the second most common cause of death

how does cancer start

it starts with one cell then multiples

what is cancer caused from

mutation and epigeneitc mechanisms that are regulated abnormally

examples of mutations that cause cancer

smoking and uv light radiation

is cancer different from other genetic disease?

yes

cancer is a genetic and epigenetic disease at the cellular level

true

in what cells do mutations usually occur in?

somatic cells (body cells)

why is cancer different from other genetic diseases

a cancer rarely arises from a single mutation. Many mutations needed in an affected cell.

what type of genes are mutated or expressed aberrantly in cancer?

DNA repair, cell cycle control, apoptosis, cellular differentiation, cell migration, and cell to cell contacts

what is cancer?

a large number of different complex diseases

what are the two fundamental properties that cancer cells share

unregulated cell division and metastic spread

what is cell proliferation?

unregulated cell division

benign tumor

cells divide abnormally but do not spread to other parts of the body

malignant tumor

cells divide abnormally and can spread to other parts of the body

metastasis

when cancer cells spread to other parts

are the cells in a tumor genetically identical

no

why do cancer cells have a clonal origin

they arise form a single cell that accumulated numerous specific mutations

what happens as a cancer cell grows

the cells gain new mutations then they divide.

subpopulations of cells

when the cells gain new mutations and divide

driver mutations

mutations that happen in genes that promote cancer

passanger mutations

does not contribute to cancer

when does passenger mutations play a role in cancer

some can give the cancer cell an advantage if their conditions chance.

what is the cancer stem cell hypothesis?

that not all cells in a cnacer proliferate. The cells in a cancer that do divide and produce the tumor are cancer.

how are cancer stem cells similar to normal stem cells

they can self renew and they can produce cancer tissues instead of normal tissues

does a cancer stem cell divide to produce two types of daughter cells?

yes

what is tumorigenesis

as mutations accumulate in a cell, it gradually progresses towards becoming a cancer cell

why is tumorigenisis a multi step process?

because cancer cells do not arise from a single mutation in a cell.

what is clonal expansion

important feature of tumorigenesis

process of clonal expansion

each driver mutation confers a growth and survival advantage to a cell. then the cell divides more rapidly than other cells and creates a subpopulation of cells (clone)

what is genomic instability

unstable genome

what characterizes the gnomic instability of cancer cells

genomic instability and epigenetic abnormalities

mutation phenotype

the high level of genomic instability in cancer cells

the genes that are altered in a cancer cell normally function in cellullar functions such as

point mutations and chromosomal alterations such as translocations, deletions, and aneuploidy

are cancer cells hypomethylated

yes

how are cancer cells characterized by their abnormal DNA methylation patterns

increased gene expression of genes that normally would not be used

increased genomic instability as noncoding portions is not methylated and thus susceptible to translocations

can cancer cells be hypermethyulated

yes

chromatin remolding complexes in cancer cells

mutations in proteins that are part of chromatin complexes can occur in cancers to abnormal chromatin remolding that can cause abnormal gene expression

histone modification in cancer cells

writers, readers, and erasers can be mutated in cancers that can cause abnormal histone modification patterns and/or cellular responses to histone modifications

what is the purpose of epigentic cancer therapy

to reprogram gene expression patterns that are characteristics to cancer cells (returning gene expression to a normal and healthy pattern)

are epigentic modifications reversible

yes

what is the focus of drug development in epigentic cancer therapy

to target genes that have been silenced by epigentic mechanisms