Hallmarks of Cancer Flashcards
What are the hallmarks of cancer? (6)
Self-sufficiency in growth signals Insensitivity to anti-growth signals Evading apoptosis Limitless reproductive potential Sustained angiogenesis Tissue invasion and metastasis
What are the characteristics of cancer cells? (5)
Increase in growth factor secretion Increase in oncogene expression Loss of contact inhibition Loss of tumour suppressor genes Neovascularization
What are the characteristics of normal cells? (3)
Oncogene expression is rare
Intermittent or coordinated growth factor secretion
Presence of tumour suppressor genes
What is meant by a ‘hallmark’ of cancer?
Essential alterations in cell physiology that collectively dictate malignant growth. These are acquired capabilities that enable carcinogenesis, tumour growth and spread.
Self-sufficiency in growth signals - what is meant by this?
Normal cells require mitogenic growth signals before they can move from a quiescent state to a proliferative state. Many oncogenes act by mimicking normal growth signalling, and tumour cells can generate many of their own growth signals, reducing their
dependence on stimulation from their normal
micro-environment.
Insensitivity to anti-growth signals - what is meant by this?
Within a normal tissue, anti-proliferative signals
operate to maintain quiescence and homeostasis, including both soluble and immobilised growth inhibitors. These are received by transmembrane cell surface receptors coupled to intracellular signalling circuits.
How do anti-proliferative signals block proliferation? (2)
- Cells may be forced out of the proliferative cycle into the quiescent (G0)
- Cells may be induced to permanently relinquish their proliferative potential by entering into post-mitotic state associated with differentiation.
Evading apoptosis - what is meant by this?
The ability of tumour cell populations to expand in number is determined by the rate of cell proliferation AND the rate of cell attrition (i.e. programmed cell death/apoptosis).
What are the emerging hallmarks of cancer? (4)
Avoiding immune destruction
Deregulating cellular energetics
(Tumour-promoting inflammation)
(Genome instability and mutation)
Define ‘oncogene’.
A cancer-inducing gene that can transform cells
Define ‘tumour suppressor gene’.
A gene whose partial or complete inactivation, occurring in either the germ line or the genome of a somatic cell, leads to an increased likelihood of cancer
developing. Such a gene is responsible for constraining cell proliferation.
Self-sufficiency in growth signals - give an example of a mechanism.
Activate H-Ras oncogene
Insensitivity to anti-growth signals - give an example of a mechanism.
Lose retinoblastoma suppressor
Evading apoptosis - give an example of a mechanism.
Loss of p53
Limitless reproductive potential - give an example of a mechanism.
Turn on telomerase
