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