Health Sciences 1001A/B Lecture Notes - Tumor Suppressor Gene, Melanoma, Canadian Cancer Society

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Published on 19 Apr 2013
School
Western University
Department
Health Sciences
Course
Health Sciences 1001A/B
Professor
Page:
of 4
Chapter 8: Cancer
Cancer:
- Abnormal and uncontrolled growth of cells
- Tumor a mass of cells with no physiological purpose
- Benign tumor only dangerous if it interferes with other body functions
- Malignant tumor cancerous, can spread to surrounding tissues (metastasis)
- Second leading cause of death in Canada (following heart disease)
- 45% of men and 40% of women will have cancer in their lifetime
- Aging populations (89% of people are diagnosed at 55 years of age)
Young Adult Cancer Risk:
- Canadian Cancer Society (2009) report on young adults (15-29 years)
- More females than males are diagnosed with cancer but slightly more men have died
from cancer
Most Challenging:
- Unknown risks
- Rare cancer types
- Aggressive behaviour
- Delayed diagnosis and treatment
Signs and Symptoms:
- Lumps in neck, breast or testes
- Isolated pain
- Fatigue
Suggestions:
- Regular physical examinations
- Prevention and screening (pap tests, HPV vaccination)
- Awareness of bodily changes
- Research on risk factors
Role of DNA:
- Oncogene: if mutated, over-activated, can be cancer causing
- Tumor suppressor gene: normal function to control cell growth
- Mutagens substances that cause mutations in DNA
- Carcinogens/cancer inhibitor mutagens that cause cancer
Lifestyle and Cancer:
- New evidences show that
lifestyle factors are
related to modifications
in DNA
- 50% of all cancers may
be preventable
Dietary Factors:
- Alcohol consumption
- Obesity/physical activity:
not correlated to BMI but
correlated to fat
consumption
- Poor diet, exercise habits
plus obesity = ~ 22% of
all cancer deaths
Environmental Toxins:
- (benzene, lead, PAH, ionization agents, exposure to UV)
- Tobacco use (both cancer inhibitor and promoter)
( ~30% of all cancer deaths, 85% of lung cancer cases)
- 87% of lung cancer cases can be prevented by avoiding tobacco exposure and exposure to
smoking can cause a decrease risk of several other cancers
Skin Cancer: Melanoma
- Easily detected and highly curable (when detected early)
- Exposure to ultraviolet rays
- Common causes sunburns and suntans
Types:
Non-melanoma:
- 81,300 peoples will be diagnosed
- 320 people would die (0.39%)
- Most common cancer case (1/3 of all cancer cases)
Melanoma:
- 5,800 people diagnosed
- 970 people will die (16.7%)
- Melanoma accounts for only 6.7% of skin cancer and yet causes 75% of all skin cancer
deaths
- Almost 4x more likely to die from melanoma than non-melanoma
- <90% of skin cancers caused by sun exposure
- Risk doubles if you have 5 or more burns
- Melanoma is the most common cancer for young adults 25-29 years old and the second
most common form of cancer for young people 15-29 years old (Skin Cancer
Foundation)
Melanoma:
- Starts in the melanocytes
- Located in the top layer of the epidermis
- Produce melanin (skin colour pigments) that darken with UV exposure
- Can cluster together to form moles
ABCD Screen:
A asymmetry one half of the mole differs
B border: - jagged, irregular
C colour: colour of the mole varies throughout, a new colour appears, and/or has increased in
size
E evolution: growth of the mole
F feel: rocky feel to the mole
G gross: oozing or bleeding
Skin Cancer Facts: Causes of malignant melanoma are more often found:
Men between the shoulders and hips
Women arms and legs
Blonde, blue eyes, fair complexion
- It is normal to develop new mole but people with 50+ moles are at higher risk
- It is normal to develop new moles during the late teens and early twenties
- Some may begin but if they differ from other moles on your body take precaution and get
a medical opinion
- Melanoma will often start out as a scab or a sore that does not heal (may bleed or itch)

Document Summary

Tumor a mass of cells with no physiological purpose. Benign tumor only dangerous if it interferes with other body functions. Malignant tumor cancerous, can spread to surrounding tissues (metastasis) Second leading cause of death in canada (following heart disease) 45% of men and 40% of women will have cancer in their lifetime. Aging populations (89% of people are diagnosed at 55 years of age) Canadian cancer society (2009) report on young adults (15-29 years) More females than males are diagnosed with cancer but slightly more men have died from cancer. Prevention and screening (pap tests, hpv vaccination) Oncogene: if mutated, over-activated, can be cancer causing. Tumor suppressor gene: normal function to control cell growth. Mutagens substances that cause mutations in dna. Carcinogens/cancer inhibitor mutagens that cause cancer. New evidences show that lifestyle factors are related to modifications in dna. 50% of all cancers may be preventable. Obesity/physical activity: not correlated to bmi but correlated to fat consumption.