MoD Neoplasia 3- Why And How Do Neoplasms Occur? Flashcards
What are intrinsic (3) and extrinsic (2) factors of cancer formation?
Intrinsic- age, gender, heredity
Extrinsic- environment, lifestyle
What are 5 risk factors of cancer?
High BMI Low fruit and veg consumption Low exercise levels Tobacco Alcohol
What are the three catergories of extrinsic carcinogens?
Chemicals, radiation, infections
What is this name of a chemical used in the dye industry? What has it showed us? (3)
2-napthylamine
- That there is a long delay between carcinogen exposure and malignant neoplasm
- Cancer risk depends on carcinogen dosage
- Can be organ specificity for carcinogens
What are initiators and promoters? What do they cause?
Initiators- mutagens
Promotors- cause prolonged proliferation.
They produce a monoclonal expansion of mutant cells.
How do procarcinogens become carcinogens?
In the liver using cytochrome P450.
What are complete carcinogens?
Carcinogens that act as promoters and initiatiors.
What is radiation?
Any type of energy that travels through space.
What two things does direct radiation damage cause?
- altered bases
- single and double strand DNA breaks
What does indirect radiation damage cause?
Free radical production.
How can infections causes mutations? (2)
- can affect genes that control cell growth
- can cause chronic tissue injury which therefore causes mutations
What cancer is HPV associated with?
Cervical
How does HPV cause carcinoma development? (2)
It expresses E6 and E7 proteins which inhibits P53 and pRB respectively. This means that DNA damage can’t be detected and either repaired, or gotten rid of by apoptosis, and cell are checked at restriction points in the cell cycle before continuing.
What inheritance pattern does retinoblastoma have?
Dominant
What is the two hit hypothesis?
The idea that familial cancers have a germ line ‘hit’ which affects all cells in the body, followed by a somatic ‘hit’ which mutates one of these already hit cells.
Where as sporadic carcinomas require 2 hits somatically, as they don’t have a genetic inheritance. For cancer to arise, the hits must be to the same cell.
