Causes and Risk factors
Which of the following is a direct cause for cancer: stress, drinking, smoking or brain injury
Smoking!
State 2 differences between malignant and benign tumors?
Malignant tumors are invasive and benign tumors are localised.
Benign tumors are non-cancerous and malignant tumors are cancerous
Proto-oncogenes help regulate the cell cycle. When they mutate what are they called?
Oncogenes
What do cancer cells have to break through to be able to metastasise?
The basal lamina
Your mom had breast cancer, your grandma had breast cancer. What gene mutation should your doctor probably test you for?
BRCA1 or BRCA2. Inherited mutations in these genes dramatically raise breast and ovarian cancer risk.
What is the difference in where sarcomas and carcinomas start?
Sarcomas start in the connective tissues
Carcinomas start in the epithelial tissues
A mutation in this gene results in a loss of function. What is this gene called?
Tumor suppressor gene!
What is the process called of cancer cells developing blood vessels and gaining their own blood supply?
Angiogenisis
A 58-year-old man has smoked one pack of cigarettes daily for 35 years. He stops smoking completely today. Which statement is MOST accurate?
A. His lung cancer risk immediately returns to baseline
B. Smoking only causes cancer through chronic inflammation
C. His risk decreases over time but remains above that of a never-smoker
D. DNA mutations caused by smoking are fully reversible
C. His risk decreases over time but remains above that of a never-smoker
List 4 cellular differences between cancer cells and regular cells
1. Large nucleus to cytoplasm ratio
2. Loss of normal specialised features
3. Variable sized nuclei
4. Disorganisation. Cells grow on top of eachother
You only need ONE faulty copy of an oncogene to cause problems, but you need to lose BOTH copies of a tumour suppressor. Why is that?
Oncogenes are dominant, one faulty copy overrides the normal one. Tumour suppressor genes are recessive, you have a backup copy, so both must be lost for function to fail.
This process contributes to cancer development because it allows cells with DNA damage to continue dividing.
A. Increased apoptosis
B. Reduced angiogenesis
C. Failure of cell cycle regulation
D. Enhanced oxygen transport
C. Failure of cell cycle regulation
What is the most prominent risk factor: poor diet, age, inactivity, coke zero (artificial sweeteners), or car accidents
Age
What causes cancer cells to have disrupted cell adhesion?
Loss/mutation of e-cadherin
A woman inherits a mutation in the BRCA1 gene.
Why does this mutation increase cancer risk?
A. BRCA1 stimulates uncontrolled mitosis
B. BRCA1 normally helps repair damaged DNA
C. BRCA1 mutations increase angiogenesis directly
D. BRCA1 only affects hormone production
B. BRCA1 normally helps repair damaged DNA
State the 4 stages of metastasis?
1. local invasion
2. intravasation
3. extravasation
4. colonisation
What is the difference between a carcinogen and a mutagen?
A carcinogen is any agent that causes cancer (could be chemical, radiation, biological). A mutagen specifically causes mutations in DNA. All carcinogens that work by damaging DNA are mutagens, but not all mutagens cause cancer.
A mutation activates telomerase expression. Explain why this may contribute to malignancy?
Activation of telomerase prevents telomere shortening, allowing abnormal cells to divide indefinitely and accumulate further cancer-promoting mutations.
What would happen to a cell if p53 stopped working properly?
Without p53, damaged cells cannot halt the cell cycle or undergo apoptosis. Mutations accumulate rapidly, chromosomal instability increases, and the cell is much more likely to become cancerous
What is the primary physiological purpose of a cancer cell coating itself with platelets-forming a 'microthrombus'-once it enters the systemic circulation? (500)
To increase the surface area for oxygen absorption
To provide a source of nutrients for anaerobic glycolysis
To trigger immediate extravasation into the bone marrow
To shield the cell from shear stress and Natural Killer (NK) cell surveillance
4. To shield the cell from shear stress and Natural Killer (NK) cell surveillance