1. Cancer and the Cell Cycle
Small cell shows a healthy white blood cell and the big cell shows and in invading cancer cell.

2. Cell Cycle Checkpoints
There are proteins that send messages to the nucleus, telling the cell whether or not to divide
A cell should remain in interphase and NOT divide if:
Signals from the surrounding cells tell the cell not to divide
There are not enough nutrients to provide for cell growth
The DNA within the nucleus has not been replicated (copied)
The DNA is damaged
If there is too much damage to the DNA, the cell is usually destroyed
This is a vital process that keeps organisms healthy

3. Cell Cycle Gone Wrong… Cancer
one or more of the checkpoints fails, so the cell and all of its subsequent daughter cells continue to divide uncontrollably
No G0 – division over and over again

4. Role of Cell Division in Cancer
Top = normal cell division
Bottom = unregulated cell division and tumour formation
Malignant
If tumor invades surrounding tissue (cancerous)
Benign
If tumor has no effect on surrounding tissue
(non-cancerous)
Apoptosis: 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. Apoptosis plays a crucial role in developing and maintaining health by eliminating old cells, unnecessary cells, and unhealthy cells. The human body replaces perhaps a million cells a second. Too little or too much apoptosis plays a role in a great many diseases. When programmed cell death does not work right, cells that should be eliminated may hang around and become immortal. For example, in cancer and leukemia. When apoptosis works overly well, it kills too many cells and inflicts grave tissue damage. This is the case in strokes and neurodegenerative disorders such as Alzheimer, Huntington and Parkinson diseases. Apoptosis is also called programmed cell death or cell suicide. Strictly speaking, the term apoptosis refers only to the structural changes cells go through, and programmed cell death refers to the complete underlying process, but the terms are often used interchangeably.
Benign – no effect on surrounding tissue
Malignant – invades surrounding tissue
Metastatic – cells break away and invade other areas
Metastatic
If individual cells break away and start a new tumor elsewhere
(cancerous)
Image from the National Cancer Institute

5. The vessels of the circulatory and lymphatic systems provide a pipeline for cancer cells to move to other locations in the body through a process called metastasis.

6. What is Cancer?
“Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled, it can result in death.”
- The American Cancer Society
Tumours
Two types:
Benign (non-cancerous) – this is not cancer!
Does not spread; it can eventually become malignant in some cases
Malignant (cancerous) – this is cancer!
Has the potential to spread to other parts of body

7. Do you know someone personally that has had cancer?

8. Overall Cancer Incidence and Mortality (death) Trends in U.S.
- Includes all sexes! The number of deaths due to cancer has been decreasing since 1990

9. Canadian Cancer Society Reports…
Approximately 83,900 Canadian women will be diagnosed with cancer and an estimated 36,200 women will die of cancer.
Approximately 90,000 Canadian men will be diagnosed with cancer and an estimated 40,000 men will die of cancer
On average, 3,340 Canadians will be diagnosed with cancer every week.
On average, 1,470 Canadians will die of cancer every week.
Prostate cancer is the most frequently diagnosed cancer in Ontario, followed by breast cancer and colorectal cancer, respectively.
- Includes all

10. Lung Tissue
A and C – normal lung tissue --- A = bronchial and C = alveolar.
B and D – invaded by cancer cells

11. Causes of Cancer
If errors occur during the replication (copying) of DNA, mutations can result
If mutations occur in the DNA that controls cell division, the cells may become cancerous and grow wildly through repeated, uncontrolled mitosis and cytokinesis
Some mutations are caused by carcinogens (environmental factors that cause cancer)
Some typical carcinogens are: tobacco smoke, radiation (x-rays, UV rays), viruses, and chemicals

12. Cancer Screening
Screening for cancer is done even though there are no symptoms
Cancer screening can be done in a number of ways, and is especially important for those who have a family history of cancers
Men and women should take responsibility for their health by performing self-tests
Other screening tests include a Pap test for women (to check for cervical cancer), a blood test for colon cancer and regular skin checks

13. Reducing Your Risk of Cancer
Many factors can increase your risk of getting cancer:
Personal and family medical history
Carcinogens in your environment
Lifestyle choices (only one you control to have a big impact on your likelihood of getting cancer)
Avoid tobacco smoke
Healthy diet (lots of fruit and vegetables, less fatty meat)
Certain cancer ‘super foods’ have been identified that contain substances that help your body protect itself from cancers (see figure 4 on page 51)

14. Diagnosing Cancer
The earlier cancer is diagnosed, the better the chances of it being successfully treated
If cancer is suspected, doctors will order medical tests to investigate further:
Imaging technologies (include endoscope, x-ray, ultrasound, CT scan and MRI) – see figures 6 – 10 on pages 52 and 53
Examining cells – look at suspected cancer cells under microscope (such as blood cell samples or a biopsy of tumour cells)

15. Treatment for Cancer Radiation Chemotherapy Surgery
There are currently three conventional methods of treating cancer:
Radiation
Uses high-energy rays to kill cancer cells
A large machine directs radiation at the body
Chemotherapy
Uses anti-cancer drugs to kill cancer cells (also kills healthy cells)
Surgery
physical removal of all cancerous tissue

16. Trends in Five-year Relative Survival (%)* Rates, US, 1975-2004
Site
Breast (female) 75 79 89
Lung 13 16
Ovary 37 40 46
Prostate 69 76 99
Colon 52 59 65
From American Cancer Society
Estimates the prognosis of the disease
Relative survival: number of people with the disease who are alive after 5 years divided by the number of the of comparable people in the general population also alive after 5 years

17. Survival Data according to Canadian Cancer Society
Based on estimates, 62% of people are expected to survive for 5 years after their cancer diagnosis compared to the general population of the same age and sex. Survival rates differ according to the type of cancer
One in 7 men will develop prostate cancer during his lifetime (the risk is highest after age 60) and one in 27 will die of it
One in 9 women is expected to develop breast cancer during her lifetime and one in 28 will die of it
One in 11 men is expected to develop lung cancer during his lifetime and one in 13 will die of it.  One in 16 women is expected to develop lung cancer during her lifetime and one in 18 is expected to die of it.

18. Inquiry: Does the Patient Have Cancer?
Title
Purpose
Observations: Graph
Complete questions #1 to 3
To be handed in before you leave class!

19. How to Make a Graph
Proper title that explains what the graph represents
Create a “best line” using a smooth curve
Label the x- and y-axes (independent variable on the x and dependent variable on the y)
Include units in the axes labels
Number the scale on both axes
Make sure the entire page is used (large graph)
Include a legend when more than one curve is graphed
- Note not all points have to be on the line

20. Follow-up to Cancer & the Cell Cycle
For Homework:
Define tumor (benign and cancerous), metastasis
‘Check Your Learning’ # 1 – 3, 7, 8 on page 55