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Cancer and the Cell Cycle
Cell Death and Cell Suicide
 Sometimes cells leave the cell cycle to die [apoptosis]
because they are damaged beyond repair or they are simply
not needed.
 Other times cells will undergo cell suicide when their
survival would be a threat to the organism
 For example, cells infected by a bacterium or virus, or if there
is a problem with its DNA.
Cell Cycle Checkpoints
How Cancer Develops
 When the cell cycle fails (ignores the checkpoints) and
abnormal cell division begins (this is caused by mutations)
 Mutations can occur due to chance (mistakes) or carcinogens
 Carcinogens include toxic chemicals, radiation and viral
infections
 Instead of dying (as instructed by checkpoints) these cells start
dividing excessively and form a tumor
 After a tumor forms, cancer may then develop when further
changes to the cells occur and they start to divide
uncontrollably
Healthy vs. Cancer Cells
Healthy Cells
Cancer Cells
 Usually don’t reproduce when  Don’t mature or carry out a
isolated from their other tissue
function.
cells. This is because they
 Cancer cells will reproduce in
communicate cell to cell.
isolation (1 cell every 24 hours
 They adhere to each other
= 1 billion/month).
well and communicate to
 Cancer cells do not adhere
work together. They keep a
well with other cells, forming a
balance between cell
tumor and increasing the risk
destruction and cell growth.
of metastasis [spread to other
areas in the body].
 Cancer invades healthy
tissue, which then cannot do
its job properly.
Normal vs Cancer cells
 Shape of cell and nucleus changes
 Large nucleus, small amount of cytoplasm
Lung Cancer development over
years
Normal Skin and Squamous Cell
Carcinoma
Detection of Cancer
 Screening:
 When a person does not have any signs or symptoms of cancer
 Includes prostate exam, mammogram, breast self-exam,
testicular self-exam, pap smear, blood tests, colonoscopy
 Typically done as a regular medical checkup once you reach a
certain age, but can be requested or done by YOU at any time
 When signs and symptoms are present:
 Usually confirmed through blood tests, biopsies, MRIs and/or
ultrasound
Treatment of Cancer
 Before treatment begins, your doctor must determine:
 The type and progression of the cancer
 Scientific evidence that the treatment works for that type of
cancer
 Patient’s age and general health
 Any other medical problems that may exist
Treatment Options
 Typically there are three treatments available to patients:
 Surgery to remove part or all of the tumor
 Chemotherapy: the use of drugs to treat cancer. These drugs
slow or even stop the growth of the cancer cells.
 Radiation therapy: the use of high energy radiation to
damage or destroy cancer cells. High doses of radiation induce
apoptosis [cell death].
Homework:
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