Lesson 8 Flashcards
(40 cards)
What is neoplasm?
Newly- formed collection of cells resulting from abnormal cellular proliferation - persists after initial stimulus is removed.
neo = new plasm = formed material
Describe a benign lipoma
Well circumscribed, slow growing, non-invasive, closely resembled the tissue of origin (fat)
Explain uterine fibroids
- Most common benign tumours in women of childbearing age
- Development of fibroids increases with age
- Present in 80-90% of all women by age 50 years.
- Cause pain, excessive menstrual bleeding or infertility
Describe meningioma
Most frequently reported primary CNS tumours (approx. 36% of all CNS tumours)
The etiology of cancer is _____________ (i.e. it is caused by _____ and ______ factors)
Multi factorial
Intrinsic
Extrinsic
Give examples of intrinsic factors?
Genetic mutations Age Ethnicity Gender Family disease history
Give examples extrinsic factors?
Environment influences/lifestyle choices:
- physical exercise - diet - weight management - tobacco intake - exposure to environmental pollutants - infections - exposure to chemical carcinogens - exposure to radiation - alcohol intake
What are some examples of carcinogenic agents?
Polycyclic aromatic hydrocarbons (PAHs) - benzopyrene -> lung/skin cancer
Aromatic amines - 2 naphthylamine -> urinary bladder disease
Nitrosamines - sodium nitrate -> gut cancers
Asbestos -> malignant mesothelioma, lung carcinoma
Most _________ enter the body as __________, which are then converted to _________ by cellular machinery
Carcinogens
Procarcinogens
Carcinogens
Describe benzopyrene
Is a procarcinogen - one of the main carcinogenic agents in cigarette smoke
Must first be oxidized by cytochrome P4501A1 -> modified by other enzymes -> benzopyrene diol epoxide -> binds covalently to DNA -> form an adduct where it causes mutations
What is the effect of ionising radiation on the body?
strips electrons from atoms and includes X-rays
Describe nuclear radiation
Arising from radioactive elements. Nuclear radiation comprises alpha particles, beta particles and gamma rays
What can UV light not penetrate?
Cannot penetrate deeper than the skin
How does radiation cause cancer?
- Radiation can damage DNA directly
- Misrepairs by DNA repair proteins allow the mutation/chromosomal rearrangement to persist
- Radiation can damage DNA indirectly by:
- Generating free radicals.
- Producing secretable soluble factors that can affect distal non- irradiated cells
What are some occupations that are associated with the development of tumours?
Construction - asbestos -> lung, stomach, larynx
Painters - solvents -> childhood brain tumours
Aircrew, nuclear worked - ionising radiation -> bone, liver, lung
Farming, agriculture - pesticides -> soft tissue sarcoma, lung
What are the stages of carcinogenesis?
Initiation - carcinogen/UV:
- irreversible genetic mutation in stem cell/progenitor cell
Pronation - tumour promoter/UV:
- clonal expansion of initiated cells within generalised hyperplasia
- outgrowth of pre-malignant tumours = papillomas
Progression:
- malignant conversion to invasive carcinoma
-> metastasis
What is the latency period in carcinogenesis?
Long interval between exposure to a carcinogen and clinically-detectable neoplasia
What are papillomas?
Papillomas are pre-malignant (benign) tumours that can ultimately progress (following the acquisition of additional mutations) to an invasive, malignant carcinoma.
Animal tests have shown that chemical carcinogens, called ______, must be given first, followed by a ______ class of carcinogens called _______
Initiators
Second
Promoters
Describe retinoblastoma
• A type of eye cancer that usually develops in early childhood <6
• Affects ~1 in every 15,000 children)
• Approximately 60% of cases are sporadic (no family history of
disease).
• Approximately 40% = family history (inherited)
• Mechanism involves loss of the retinoblastoma protein RB the
prototypic tumour suppressor gene
Loss of _____ __________ gene function explains the susceptibility of developing _____________
Tumour
Suppressor
Retinoblastoma
Describe the inheritance pattern for high risk bilateral retinoblastoma
Inherited mutation or absence of one of the paired RB1 genes
Mutation or loss of RB1 gene in any retinal cell
Describe the inheritance pattern for sporadic retinoblastoma
Normally paired RB1 genes
Mutation or loss of one RB1 gene
Mutation or loss of the other RB1 gene in same cell or its daughter cells
Describe familial breast cancer (BC)
- BC is the primary cause of cancer- related deaths in women globally.
- Familial BC - accounts for ~12% of all BC cases
- Mutations in either BRCA1 or BRCA2 genes, encode BRCA1/BRCA2 tumour suppressor proteins, involved in repairing DNA double-strand breaks feature in ~20-50% of familial BC cases
Mutations in BRCA1/2 are also associated with ovarian cancer, prostate cancer and pancreatic cancer
