Transcript Cell Biology Cancer 2

Biomedical Technology
Cell Biology and Cancer
Objective 2
Causes
and
Development
of Cancer
What causes cancer?
The Known Agents
Ultraviolet Radiation
Radium
Coal tar
Cigarette Smoke
Asbestoses
What does cancer represent?
It represents a
breakdown of the
processes that
regulate the growth
of normal cells and
tissues.
What happens when a person
develops cancer?
Cancer cells multiply rapidly, taking up
space and nutrients from the normal
cells.
A once precisely regulated system
of cell division goes wild !
Cancerous growth
disrupts and allows
uncontrolled
division of body
cells.
How exactly does cancer cause all
this trouble?
First: Look at “Normal Cell Division”
• Cell division rate is normally controlled by
two genes.
• These genes are able to send messages
from cell to cell telling them when to
replicate, when to stay the same or when to
die.
• The genes regulate
cell growth by
activating the “cell
cycle clock” found in
each cell body.
• Cancer gains control
or disrupts this
mechanism and the
result is
overcrowding and
inadequate nutrition
to support the
increased cell
growth.
Introducing !
The Stages of Tumor
Development
Tumors: A mass of cancer cells
Stage 1:
Mutation
• The first stage of cancer
• The mutation starts in the genetic
make up of the cells
• Causes cells to start multiplying
and dividing more rapidly that it
normally would.
Stage 2:
Hyperplasia
• Second stage of cancer development
• Enlargement of a part due to an abnormal
numerical increase of its cells.
• Increase of number of cells leads to
enlargement of tissue or organ involved.
• Considered a pre-cancerous stage.
Stage 3:
Dysplasia
• Abnormal cells that
are not cancer
• Starts to increase
the size of tissue or
organ
Stage 4:
In Situ cancer (tumor)
• Cancer that has
remained within the
original tissue where
it started.
• Has not started to
spread to other parts
or tissues
surrounding it.
Stage 5: Invasive cancer (malignant)
• Invades nearby
tissues
• Cells can shed from
the primary tumor
into the blood or
lymph and invade
other parts of the
body.
Tumors threaten an individual’s
life when their growth disrupts
the tissues and organs needed
for survival.