Cancer - Environmental / Behavioural Factors

Cancer definition

A large collection of related disease that are characterised by abnormal cell functioning

Effect of Genetic Alterations (5)

Proliferation

Apoptosis

Tissue invasiveness

Production of Growth and Angiogenic factors

Ability to escape immune survaeillance

Carcinogenic factors

Primary

Chemical

Viral

Bacteria

Secondary

Heriditary

Favouring Factors

Lifestyle

Nutrition

Geographical factors

Sex

Age

Environmental Factors

Neoplasm

Abnormal growth of tissues that may or may not be cancerous (tmour)

Radiation

Ultraviolet radiation

Ionising radiation

Types of Radiation

Radon gas

Types

Infectious agents

UVB

UVA

Burning and skin cancer

H. pylori

HPV

Hep B

Hep C

Epstein Barr Virus

Human herpesvirus 8

Stomach cancer

Liver cancer

Liver cancer

Cervical cancers + Oral cancer

X rays and γ rays

Cosmic rays

Sensitive Tissue

Highest mitotic activity

Lymphoid tissue

Bone marrow

Mucosa of GI tract

Germical tissue

Acute leukemia

Papillary carcinoma of the thyroid

Aging and skin cancer

Cancer types

Malignant melanomas

Basal cell carinomas

Squamous cell carcinomas

Lifestyles Factors

Diet (Obesity)

Cause of Obesity

High caloric diet rich in fat, refined carbs and animal protein

Low physical activity

MOA

Prevention and Control

Primary

Reducing exposure to risk factors

Secondary

Early detection - Screening

PAP smears

Breast screening

Colorectal screening

Cervical precancerous absnormalities - HPV and Cytology

Vaccination against HPV virus

Mammograms

Faecal immunochemical test (FIT)

Age

Occupation

Caused by an accumulation of genetic alterations that give a survival advantage to the neoplastic cell

– RB1 (retinoblastoma)

– APC (familial polyposis)

– Human Non Polyposis Colon Cancer (HNPCC-Lynch Syndrome)

– BRCA 1&2 (breast and ovarian cancer)

– p53 (many cancers, Li Fraumeni Syndrome)

Smoking

Alcohol

1/4 of all cancer deaths
1/5 cancer cases
9/10 lung cancer patients smoke

Carcinogens - Over 20

Tar
Polycyclic aromatic hydrocarbons
Nicotine
Phenol
Benzopyrene
Carbon monoxide
Formaldehyde
Nitroasmine

7 cancers

Bowel
Breast
Mouth
Upper throat
Larynx
Osephagus
Liver

MOA

ROS from acetaldehyde damages cells
Weakens ability to absorb nutrients - no protection
Increase in oestrogen level - breast cancer
Weight gain
Acetaldehyde build up - leads to cancer development

Processed Meat

Group 1 classification

Nitrates and nitrites

Preserve meat

Increase risk of cancer

Haem in Red meat

Damage cells / introduce new chemicals into cells

MOA

Free radical formation causing DNA damage
Direct DNA damage from radiation

Cancer Types

Acute leukemia

Papillary carcinoma

Thyroid

Double stranded DNA break
Failed or abhorrent repair - carcinogenesis

13 cancers

Bowel and breast

Insulin resistance
Hyperinsulinemia
Increases bioavailability of IGF-1
Increased cell proliferation + deacreased apoptosis
Tumour growth, cancer

Fat cell produces oestrogen
Breast and ovarian cancer

Obesity causes inflammation
Macrophages clean up dying fat cells
Induce cytokines
Chronic inflammation
Linked to cancer development

MOA

Polycyclic aromatic hydrocarbons

Introduce gene mutation and effect gene expression
Lead to formation of reactive oxygen species which cause cancer
Cause the activation of cytochrome P450

Formadehyde

Produce DNA crosslinks
Causes chromosome deletions and rearrangements

Isoprene

Single and double strand breaks in DNA