Cancer Flashcards
what are the hallmarks of cancer?
- Self-sufficiency in growth signals (oncogenes)
- Insensitivity to antigrowth signals (tumour suppressors)
- Evasion of apoptosis
- Replicative immortality (telomerase)
- Sustained angiogenesis
- Tissue invasion and metastasis
- Reprogramming of energy metabolism
- Evasion of immune destruction
what are the 7 oncoviruses for cancer?
- Epstein-Barr Virus (EBV)
- Human Papillomavirus (HPV)
- Hepatitis B (HBV)
- Hepatitis C (HCV)
- Human T-cell lymphotropic virus-1 (HTLV-1)
- Human Herpesvirus-8 (HHV-8)
- Merkel Cell Polyomavirus (MCPyV).
Which phase of the cell cycle is responsible for DNA replication?
S phase
What is the function of the G1 checkpoint?
Determines if the cell has enough resources and no DNA damage before division
What is the primary function of telomerase in cancer cells?
Maintains telomere length to allow unlimited division
Which of the following is an example of an oncogene?
RAS
Which cell cycle regulator forms a complex with cyclin to drive cell cycle progression?
CDK (Cyclin-dependent kinase)
What happens at the spindle checkpoint?
Ensures chromosomes are properly attached to spindle fibers
How does p53 respond to DNA damage?
Stops the cell cycle and activates DNA repair or apoptosis
What is the role of the RB (retinoblastoma) protein in the cell cycle?
Controls the G1-S restriction point
Which mutation sequence is commonly observed in colorectal cancer progression?
APC → K-RAS → DCC → p53
What is the function of the anaphase-promoting complex/cyclosome (APC/C)?
Triggers the destruction of M cyclins to exit mitosis
What is the role of cyclins in the cell cycle?
Control cell cycle progression by activating CDKs
Which gene is most commonly mutated in human cancers?
p53
How do tumour suppressor genes function in normal cells?
Inhibit cell division and promote apoptosis
Which phase of mitosis is characterized by chromosome alignment at the cell’s equator?
Metaphase
Why do cancer cells have unlimited replicative potential?
Activation of telomerase maintains telomere length
What happens if a chromosome is not properly attached to the spindle at the M checkpoint?
The cell pauses mitosis until proper attachment occurs
Which of the following is an example of a tumour suppressor gene?
RB
How do growth factors contribute to cell cycle progression?
Trigger signal transduction pathways that promote division
What is the role of CDK inhibitors?
Block CDK activity to halt the cell cycle when needed
What is the key difference between necrosis and apoptosis?
Apoptosis is programmed and does not cause inflammation
What happens to a cell that fails to meet the G2 checkpoint requirements?
It undergoes apoptosis or repairs the DNA
What is the role of p53 when DNA damage is detected?
Stops the cell cycle and promotes DNA repair or apoptosis
What is a major consequence of losing functional RB protein?
Unregulated entry into S phase
What is a tumour?
A mass of cells resulting from uncontrolled proliferation
What percentage of cancers are inherited?
2-3%
What is the primary function of tumour suppressor genes?
Repair damaged DNA and regulate the cell cycle
Which high-risk HPV strains are associated with cervical cancer?
16 and 18
Helicobacter pylori is associated with which type of cancer?
Gastric carcinoma
What is metaplasia?
Reversible transformation of one fully differentiated cell type into another
What does the “T” in TNM staging stand for?
Tumour size
What type of tumour arises from connective tissue and is malignant?
sarcoma
What term describes the spread of cancer cells to a distant site?
Metastasis
Germ line point mutation
affects every cell type in your body
Somatic point mutation
Only effects individual cell
What is an oncogene?
A gene that promotes uncontrolled cell division when mutated
What is the most common type of cancer in humans?
skin cancer
Which of the following is a characteristic feature of cancer cells?
Loss of differentiation (anaplasia)
Which of the following best describes tumour angiogenesis?
Formation of new blood vessels to supply the tumour
What is the hallmark of malignant transformation?
Invasion and metastasis
A well-differentiated tumour is more likely to be:
Benign
What type of malignancy originates from glandular epithelium?
Adenocarcinoma
Which feature differentiates carcinoma in situ from invasive carcinoma?
No invasion beyond the basement membrane
What is the significance of the “N” in the TNM staging system?
Lymph node involvement
Which of the following is the primary cause of Burkitt’s lymphoma?
Epstein-Barr virus (EBV)
Which of the following is the main cause of hepatocellular carcinoma?
Hepatitis B and C infections
What is the most common site of metastasis for breast cancer?
bone
What type of mutation is commonly caused by UV radiation?
CC to TT mutations
Which of the following is an example of an exogenous DNA-damaging factor?
UV light
Which disorder results from a deficiency in ATM, leading to neurodegeneration and radiosensitivity?
Ataxia-telangiectasia
Aflatoxin B1 exposure is strongly associated with which type of cancer?
Liver cancer
Which enzyme is responsible for repairing alkylation damage in DNA?
MGMT
Nucleotide excision repair (NER) is primarily used to correct which type of damage?
Thymine dimers and bulky lesions
Which genetic disorder results from a defect in nucleotide excision repair, leading to extreme UV sensitivity?
Xeroderma pigmentosum
Which pathway repairs double-strand DNA breaks without using a template?
Non-homologous end joining (NHEJ)
What is the main role of cytochrome P450 enzymes in carcinogenesis?
Convert pro-carcinogens into active carcinogens
In the “two-hit hypothesis,” what happens when both alleles of a tumour suppressor gene are lost?
Uncontrolled cell proliferation occurs
Familial adenomatous polyposis (FAP) is associated with mutations in which gene?
APC
Which cancer syndrome is characterized by mutations in mismatch repair genes such as hMSH2 and hMLH1?
Hereditary non-polyposis colorectal cancer (HNPCC)
What is the primary consequence of defective mismatch repair (MMR)?
Increased microsatellite instability
The Philadelphia chromosome is associated with which type of cancer?
Chronic myeloid leukemia (CML)
Which process allows cancer cells to evade programmed cell death?
Upregulation of BCL-2
Which chemical carcinogen is found in cigarette smoke and causes DNA adduct formation?
Benzo[a]pyrene
Which of the following viruses is strongly associated with cervical cancer?
Human papillomavirus (HPV)
Which enzyme is responsible for maintaining telomere length in cancer cells?
Telomerase
Which of the following best describes the “Warburg effect” in cancer cells?
Increased glycolysis even in the presence of oxygen
Which DNA repair pathway is defective in individuals with hereditary breast cancer due to BRCA1 mutations?
Homologous recombination (HR)
Which stage of carcinogenesis is characterized by irreversible genetic mutations?
Initiation
Which gene mutation is associated with Li-Fraumeni syndrome?
p53
How do tumour cells evade immune destruction?
Downregulation of MHC class I molecules
