Cellular Proliferation & Carcinogenesis

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Questions and Answers

What is a characteristic feature of cancerous cells in terms of cellular proliferation?

They respect the boundaries of surrounding cells.

They have no regard for cellular boundaries. (correct)

They maintain normal growth patterns.

They predominantly grow in specific tissues.

How does defective cellular differentiation occur in cancer cells?

Mature cells begin to perform additional functions.

All cells function at their highest potential.

Cells progress from a mature state back to an immature state. (correct)

Normal differentiation processes are accelerated.

Which of the following is considered a potential carcinogenic agent?

Normal immune responses

Bacteria

Oncogenic viruses (correct)

Healthy dietary habits

What effect do chemical carcinogens have on cells?

They cause cell mutation or alteration in cell functions. Signup and view all the answers

What is the main implication of the 'Failure of the Immune Response Theory' in relation to carcinogenesis?

Prolonged viral infections can overwhelm the immune system. Signup and view all the answers

Which demographic group is more prone to breast cancer?

Women with late menopause Signup and view all the answers

What is a common cause of lung cancer?

Tobacco use Signup and view all the answers

Which factor increases the risk of prostate cancer?

Positive family history Signup and view all the answers

How does urban residency relate to cancer incidence?

It is linked to greater exposure to carcinogens Signup and view all the answers

What type of cancer is associated with obesity?

Breast and colorectal cancer Signup and view all the answers

Which of the following is an example of a precancerous lesion?

Senile keratosis Signup and view all the answers

What is a key influence on the geographic distribution of cancer types?

Environmental factors like national diet Signup and view all the answers

What lifestyle factor is associated with colorectal cancer?

High-fat, low-fiber diet Signup and view all the answers

Which of the following compounds is associated with the manufacture of plastics?

Vinyl chloride Signup and view all the answers

What type of cancer is commonly linked with the use of estrogen as a replacement therapy?

Vaginal and cervical adenocarcinoma Signup and view all the answers

Which of the following factors does NOT contribute to genetic predisposition to cancer?

Increased physical activity Signup and view all the answers

Which of the following is a common carcinogenic agent found in smoked meats?

Polycyclic aromatic hydrocarbons Signup and view all the answers

Which of the following is a risk factor associated with multiple deliveries?

Cervical adenocarcinoma Signup and view all the answers

What type of food contaminant is linked with the presence of mold in peanuts and grains?

Aflatoxins Signup and view all the answers

Which physical agent is most commonly associated with cancer risk due to its ionizing nature?

UV radiation from sunlight Signup and view all the answers

Which of the following is a common example of a cytotoxic drug identified in carcinogenic agents?

Melphalan Signup and view all the answers

Study Notes

Cellular Proliferation & Differentiation

Cancer cells disregard cellular boundaries and grow over each other and normal cells.
Normal cells differentiate from immature to mature cells with specific functions.
Cancer cells dedifferentiate, reverting back to immature states.

Etiologic Factors (Carcinogens)

Viruses:
- Oncogenic viruses can contribute to carcinogenesis.
- Prolonged infections can overwhelm the immune system ("Failure of the Immune Response Theory").
Chemical Carcinogens:
- Cause cell mutations and alter cell enzymes and proteins, leading to altered replication.
- Examples:
  - Industrial compounds: vinyl chloride, polycyclic aromatic hydrocarbons, fertilizers, dyes, drugs (tobacco, alcohol, cytotoxic drugs)
  - Hormones: estrogen, diethylstilbestrol (DES)
  - Foods & preservatives: nitrates, talc, food sweeteners, nitrosamines, aflatoxins, polycyclic hydrocarbons
Physical Agents:
- Radiation: X-rays, radioactive isotopes, sunlight/ultraviolet rays
- Physical irritation/trauma: pipe smoking, multiple deliveries, jagged teeth, overuse of body parts
Hormones:
- Estrogen replacement therapy linked to increased vaginal and cervical adenocarcinoma.
Genetics:
- Oncogenes are hidden genetic codes for cancer, activated by carcinogens, leading to malignancy.
- Familial patterns exist for cancers like retinoblastoma, pheochromocytoma, Wilm's tumor, lung cancer, breast cancer.

Predisposing Factors

Age:
- Older individuals are more prone to cancer due to longer carcinogen exposure and potential immune system alteration.
Sex:
- Women are more prone to breast, uterus, and cervix cancer.
- Men are more prone to prostate and lung cancer.
Urban vs. Rural Residence:
- Cancer is more common in urban areas due to higher carcinogen exposure.
Geographic Distribution:
- Variations exist in cancer types due to environmental factors like diet, customs, and pollution (e.g., stomach cancer in Japan, breast cancer in the USA).
Occupation:
- Increased risk for individuals working in chemical factories, farming, or radiology.
Heredity:
- Positive family history increases cancer risk.
Stress:
- Depression, grief, anger, and life stresses suppress immune function, potentially promoting cancer growth.
Precancerous Lesions:
- These lesions can transform into cancerous tumors (e.g., pigmented moles, burns scars, senile keratosis, leukoplakia, benign polyps, fibrocystic disease of the breast).
Obesity:
- Linked to increased risk of breast and colorectal cancer.

Common Causes per Cancer Types

Breast Cancer:
- Early menarche, late menopause, nulliparity, or first childbirth after age 30.
Lung Cancer:
- Tobacco use, asbestos exposure, radiation exposure, air pollution.
Colorectal Cancer:
- Higher incidence in men, familial polyposis, ulcerative colitis, high-fat, low-fiber diet.
Prostate Cancer:
- Common in men over 50, highest incidence in African Americans, positive family history, cadmium exposure.

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Description

Explore the mechanisms of cellular proliferation and differentiation in cancer biology. Understand how cancer cells behave differently from normal cells and identify various etiology factors, including viruses, chemicals, and physical agents that contribute to carcinogenesis.