BPS 1101 Lecture Notes - Lecture 6: Prostate Cancer, Stomach Cancer, Programmed Cell Death
16 Dec 2016
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Drugs 101 - Cancer
- Cancer is uncontrolled growth
- 2 types of tumors (also referred to ask hyper-proliferative lesion):
1. Benign Tumor: non-life threatening growths (cyst, wart, etc in developed countries);
- Often localized & don't interfere w/ rest of body functioning
- Benign lesions can be fatal in developing countries
2. Malignant Tumor: life threatening & mobile; body part grows uncontrollably & takes over;
- Often cancer
- Cancer is #2 cause of death in North America after heart disease
- Cancer is a disease of the aged;75% of all cases occur after age 55
- Increased cancer frequency in aged associated w/ increase life span; earlier ple died b4 developed
- Cancer in children is extremely rare; almost 0%
- Cancer doesn't always cause death; if survive unpleasant cancer treatments, likely to survive cancer
- Cancer death rates decreasing for some: stomach, colon, & prostate cancer
- Lung cancer = huge increase
Change in the US death rates* by cause, 1950 & 2001
- 1950 vs 2001 = cancer death rate 0.2% high in 01 vs other rates for major chronic diseases decreased
Cancer death rates*, US
- Lung cancer is the most common cause of death & men get it more
• Incidence of lung cancer skyrocketed since 50s
- Women smoke less than men = reflected on cancer
The age-adjusted death rate from all cancers combined stabilized from 1998 to 2000, after decreasing
from 1990 to 1998. The stabilization of death rates, during the most recent time period may be due, in
part, to changes in the classification and coding of causes of death.
Compared to the rates in 1990, the cancer death rate in 2000 was 10.7% lower in men and 4.2% lower in
women.
US Cancer death rates*, men
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- Men get more cancer vs woman cuz woman are smarter than men
Most of the increase in cancer death rates for men prior to 1990 was attributable to lung cancer.
However, since 1990, the age-adjusted lung cancer death rate in men has been decreasing. Stomach
cancer mortality has decreased considerably since 1930. Death rates from prostate and colorectal
cancers have also been declining.
US Cancer death rates*, women
Currently, the lung cancer death rate in women is about two-and-a-half times what it was 25 years ago,
and lung cancer is the most common cause of cancer death. In comparison, breast cancer death rates
were virtually unchanged between 1930 and 1990, and have since decreased. The death rates for
stomach and uterine cancers have decreased steadily since 1930; colorectal cancer death rates have
been decreasing for over 50 years
What Is Cancer?
- Normal cells become cancerous when Cancer cells makes own parasite & takes over body functions
- If left untreated, cancer cells can kill you via parasite infection
- This occurs by changing the way normal cells grow
- Normal cell growth is closely regulated
1. Cells divide only o coad
2. Maximum of 50 cell divisions
3. Cells must be touching similar cells; cell removal from tissue causes apoptosis (occur so cells from diff
tissues don't wander around body)
- Cancer cell growth is uncontrolled
1. Cells divide continuously
2. More than 50 cell divisions (immortal)
- Ex: HeLa cells from Henrietta Lacks 1951
3. Malignant cells are often mobile (metastisis)
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- Every cancer is different;
- Every tissue can spawn more than 100 forms & Each tumor is unique
- Basic processes are similar
- Cancer requires 8 to 10 mutations to occur in the same cell (rare) & Requires 20 years to develop
- For this reason, there'll never be one single cure for cancer
How Cancer Affects the System:
- Biological signals are cascading processes which involve many separate, unrelated reactions.
- Biological regulation is complex & cell division is regulated in 2 ways (division occur in same way)
1. Stimulation (accelerator)
2. Repression (brakes): act in an antagonistic fashion; pathway broken in cancer(car accelerator & brakes)
- Cell growth signal system is complex & Cancer mutations involve loss of function
- Impossible to repair the function with small molecules
- Caot repair daage ith toda’s teholog; Geeti repair epesie, diffiult/ureliale-
Whe utatio disrupts ells rake sste, otiuous proliferatio ours ("off switch" cell growth broken)
- p53: an important braking protein & also an important suicide protein
- In the normal system, programmed cell death (apoptosis) protects the body from viruses and cancer.
When a protein such as p35 is disrupted, this can no longer occur.
- Every day, at least one cell in our body is cancerous, but it is usually kept in check by either the
od’s defeses or apoptosis
- In normal cells, the max number of divisions is controlled by the shortening of telomeres. However,
cancer cells are able to repair their telomeres using the enzyme telomerase, the gene for which is silent
in most cells.
- Cancer cells can also stimulate angiogenesis; the production of blood vessels directly to the tumour.
- Some individuals are more susceptible to cancer than others. These individuals often possess
oncogenes; genes that are more easily mutated to induce cancer
- In normal system, Apoptosis (programmed cell death) protects body from viruses & cancer
- This can't occur any longer when protein p35 is disrupted = detrimental effects
- Everyday, at least 1 cell in our body is cancerous but kept in check by body's defenses or apoptosis
- Programmed cell death in embryo development
- Programmed cell death in wound healing
- Programmed cell death protects body from viruses & cancer
- Normal cell division regulated by chromosome ends 'telomeres' but become frayed w/ age
- Cancer cells can repair their telomeres using enzyme telomerase, silent gene in most cells
- Cancer cells can also stimulate angiogenesis (production of blood vessels directly to tumor)
Gene:
- Gene is a set of instructions to make protein & uses 3 letter words called codons
- Each codon specifies an amino acid in a protein & amino acid sequence determines protein structure
- Certain chemical structure results in protein folds protein shape determine protein function
- Mutatio is a tpo i the gee; if protein folds in diff shape, it doesn't work anymore
Genetic Susceptibility:
- Some individuals are more susceptible to cancer than others; often possess Oncogenes
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
2 types of tumors (also referred to ask hyper-proliferative lesion): benign tumor: non-life threatening growths (cyst, wart, etc in developed countries); Often localized & don"t interfere w/ rest of body functioning. Benign lesions can be fatal in developing countries: malignant tumor: life threatening & mobile; body part grows uncontrollably & takes over; Cancer is #2 cause of death in north america after heart disease. Cancer is a disease of the aged;75% of all cases occur after age 55. Increased cancer frequency in aged associated w/ increase life span; earlier ple died b4 developed. Cancer in children is extremely rare; almost 0% Cancer doesn"t always cause death; if survive unpleasant cancer treatments, likely to survive cancer. Cancer death rates decreasing for some: stomach, colon, & prostate cancer. Change in the us death rates* by cause, 1950 & 2001. 1950 vs 2001 = cancer death rate 0. 2% high in 01 vs other rates for major chronic diseases decreased.
