Cancer 1 Flashcards
(20 cards)
What are the four main fates of a normal cell?
Survival/quiescence, proliferation, differentiation, and death (apoptosis)
How is cell fate regulated in normal tissues?
Through both intrinsic (within the cell) and extrinsic (from the environment) signals.
What defines a tumour at the cellular level?
A swelling mass made up of multiple tumour cells, not a single mass.
What gives cancer cells a growth advantage over normal cells?
Autonomous growth signals and lack of sensitivity to growth inhibition.
Why do normal cells eventually stop dividing?
Due to senescence and programmed death, regulated by cellular signals.
What are the six hallmark capabilities cancer cells must acquire?
- Sustained angiogenesis
- Self-sufficiency in growth signals
- Insensitivity to anti-growth signals
- Evasion of apoptosis
- Limitless replication
- Tissue invasion/metastasis.
What allows cancer cells to sustain angiogenesis?
proteins such as VEGF (vascular endothelial growth factor)
What causes self-sufficiency in growth signals in cancer cells?
Gain-of-function mutations in oncogenes
How do cancer cells become insensitive to anti-growth signals
Loss-of-function mutations in tumour suppressor genes.
How do cancer cells maintain limitless replication?
By producing telomerase
Which protein aids cancer cells in tissue invasion and metastasis?
Matrix metalloprotease 2 (MMP-2).
Which protein helps cancer cells evade apoptosis?
Bcl-2.
Which hallmark of cancer is not usually seen in benign tumours?
Tissue invasion and metastasis.
What types of changes in DNA can lead to cancer?
Mutations, chromosomal rearrangements, epigenetic changes, and insertion of viral genes.
What is the “multiple hit theory” of cancer development?
Many sequential genetic changes (hits) are required in a single cell over time to develop cancer.
Why does cancer incidence increase with age?
Longer exposure to mutagens and more time for mutations to accumulate.
What is clonal expansion in cancer development?
The process where a mutant cell proliferates, increasing the chances of acquiring additional mutations.
What is the significance of high-throughput genome sequencing in cancer?
It confirms that tumour cells originate from a single parent cell (clonal origin)
What leads to clonal diversity within a tumour?
Continued mutation accumulation due to defective DNA repair and checkpoint systems.
What increases the speed of cancer development in individuals with inherited mutations?
One “hit” is already present at birth, so fewer additional hits are needed to trigger cancer, and so cancer develops faster
- they are not more susceptible to cancer-forming mutations
