Introduction to Cancer Flashcards
Features of normal cell growth?
Slow, tight control, cells divide when new cells are required
What are examples of when cells divide a lot?
Wound, lactating
Definition of cancer?
A disease of cells that proliferate at inappropriate times and locations within the body.
What is a tumour?
Growing mass of cells.
How is cel growth regulated?
Checkpoints at G1/S border etc.
What are growth factors needed for?
Cell growth/differentiation
How many growth factors are there?
200.
What effects can the growth factors have?
- Regulation of cell cycle progression.
- Cell survival.
- Cell migration.
- Cell death
How do growth factors regulate the cell cycle?
They stimulate normal and cancer cells to move from the quiescent state (G0) to G1.
How do growth factors regulate cell death?
If growth factors are removed, apoptosis is favoured. Their presence inhibits apoptosis.
How do growth factors work?
Growth factors bind to a specific receptor. The growth receptor undergoes conformational change. This stimulates signal at inner side of plasma membrane. Signals sent the nucleus which cause gene transcription.
What are examples of growth factors?
Platelet derived growth factor, epidermal growth factor, erythropoietin (EPO)
What is EPO used for?
treatment of anaemia of renal disease. stimulates proliferation of red cells and their differentiation.
What does GM-CSF do?
Stimulates blood stem cell proliferation and mobilisation.
What changes do cancer cells show in terms of growth factors?
growth factors or their receptors are over active or active inappropriately. thus the cells constantly divide and grow.
What are ways that normal cells limit cell proliferation?
- maturation of a cell into a resting or quiescent state. cancer cells ignore signals to enter g0 and keep proliferating.
- post mitotic differentiation.cells undergo terminal differentiation and leave cell cycle, so pool of replicating cells decreases. cancer cells don’t differentiate and keep dividing.
- apoptosis. cancer cells ignore apoptosis.
What are types of cells that turn over rapidly?
skin, bone marrow, lining of intestine.
What happens after a cell differentiates into another cell?
it has reached it’s final specialised form. it permanently leaved cell cycle.
How quickly do cancer cells grow?
faster than neighbouring cells, so will progress through cell cycle very quickly. hence less time for DNA repair, so more mutations.
how many mutations are needed to reach cancer stage?
4-6.
why is cancer more common in old people?
bc it takes a long time for a single mutant cell to proliferate into a palpable tumour.
What is a metastatic tumour?
secondary tumours that have moved and are growing in different parts of the body.
phenotypic characteristics of cancer cells?
- don’t stop dividing when they contact a neighbouring cell. creates growth in clumps.
- reduced requirement for growth factors for same proliferation level.
- resistant to growth inhibitory signals.
- immortal. - don’t stop dividing after a predetermined number of divisions.
- changes to chromosome structure and number.
cancer cells and telomeres?
cancer cells lengthen telomeres through activation of telomerase, to cell continues to survive and doesn’t undergo apoptosis.
Growth properties of cancer cells?
- don’t need attachment to physical substrate.
- not contact inhibited.
- normal cells attach to bottom of petri dish to grow. focal adhesion.
other characteristics of cancer cells?
- enlarged nucleus.
- changes to cytoskeleton.
- absence of specialised features.
- higher metabolic rate.
tumour?
growing mass of cancer cells derived from one cancer cell
carcinoma?
skin or epithelial tissue lining body organs
sarcoma?
bones, muscles, blood vessels.
lymphoma?
lymphoid cells.
leukaemia?
wbc.
