1. Cancer and the Cell Cycle

2. 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.

4. Cell Cycle Checkpoints

5. 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

6. Healthy vs. Cancer Cells
Healthy Cells
Cancer Cells
Usually don’t reproduce when isolated from their other tissue cells. This is because they communicate cell to cell.
They adhere to each other well and communicate to work together. They keep a balance between cell destruction and cell growth.
Don’t mature or carry out a function.
Cancer cells will reproduce in isolation (1 cell every 24 hours = 1 billion/month).
Cancer cells do not adhere well with other cells, forming a tumor and increasing the risk of metastasis [spread to other areas in the body].
Cancer invades healthy tissue, which then cannot do its job properly.

7. Normal vs Cancer cells Shape of cell and nucleus changes
Large nucleus, small amount of cytoplasm

8. Lung Cancer development over years

9. Normal Skin and Squamous Cell Carcinoma

10. Detection of Cancer Screening: When signs and symptoms are present:
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

11. 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

12. 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].
Apoptosis is a form of cell death in which a programmed sequence of events leads to the elimination of cells without releasing harmful substances into the surrounding area.

14. Homework:
READ Chapter 2