Cancer (objectives only) Flashcards
What three characteristics are necessary for a classification of malignant?
- Abnormal cells
- Dividing without control
- Can invade nearby tissues
What are the six hallmarks of cancer?
- Evading apoptosis
- Self-sufficiency in growth signals
- Insensitivity to anti-growth signals
- Tissue invasion and metastasis
- Limitless Replicative potential
- Sustained angiogenesis
Describe the result of cancers ability to evade apoptosis.
the inherent cell suicide program is important in normal developmental processes, and in adults, apoptosis can serve as a safety net of sorts, because normal cells that accumulate excessive DNA damage undergo apoptosis. Unlike normal cells, cancer cells are resistant to apoptosis, and thus they continue to grow and divide even as they accumulate mutations.
Describe what is meant by cancers self-sufficiency in growth signals.
cancer cells no longer need to receive positive growth signals from other cells and tissues. Instead, cancer cells can either make their own growth hormones or they have changed so that they behave as if a growth stimulus were present even in the absence of growth hormone.
Describe the importance of insensitivity to anti-growth signals for cancer.
inability to respond normally to cues that regulate growth. For example, many cells in a healthy adult body are not actively dividing, because they are receiving signals telling them not to grow. Many cancer cells become insensitive to such anti-growth signals, thus fueling their uncontrolled growth and division.
Explain the concept of tissue invasion and metastasis.
In order for cancer to spread, cells must acquire mutations that turn on genes which allow them to break free from the primary tumor, travel through the blood stream, and establish a new colony of cells at another site in the body (ability comes from 2 and 3).
Explain how cancer achieves a limitless replicative potential.
Cancer cells can lengthen their telomeres (by turning on telomerase), thus allowing them to divide an indefinite number of times
Why is it important for cancer to have sustained angiogenesis?
the growth and division of a community of cells that has acquired some of the hallmarks of cancer will stall unless that tiny tumor figures out how to get the nutrients it needs to fuel continued growth and division. This process of recruiting new blood vessels is called angiogenesis.
Explain the normal role of a tumor suppressor gene. What happens when this is mutated? How many mutations are normally necessary in cancer?
inhibit cell wall proliferation or stimulate apoptosis when needed. Gene protects a cell from progressing towards cancer. Mutations of tumor suppressor genes cause a loss or reduction in function. Normally need damage to both genes to cause cancer.
A mutation in what produces an oncogene? What does this result in?
mutation of a normal proto-oncogene which stimulates cell proliferation. Mutagens, Carcinogens, Viruses, Irradiation and Genetic Predisposition transform a normal proto-oncogene which are essential for cellular functions into the cellular oncogene which is responsible for altered cellular functions leading to a spontaneous neoplasm.
What type of protein becomes an oncogene?
Growth factors, growth factor receptors and signal transducing proteins.
Are tumor suppressor mutations dominant or recessive?
Recessive.
A germ-line mutation involves which cells? Why?
All of your cells because it is hereditary.
Somatic gene mutations involve which cells? Why?
Affected cells because the variations are often due to the environment. Not hereditary.
Are proto-oncogene mutations dominant or recessive?
Dominant.
