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Flashcards in Introduction to Cancer Deck (25)
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what is cancer?

A group of diseases characterised by unregulated cell growth and the invasion and spread of cells from the site of origin.


what is a carcinoma?

a cancer of the epithelial cell


what is a sarcoma?

a cancer of the mesoderm cells (e.g. muscle and bone)


what is an adenocarcinoma?

a cancer of the glandular tissue (e.g. breast).


what are the hallmarks of cancer and what do they mean?

growth signal autonomy (growth signal-independent growth)
evasion of growth inhibitory signals
avoiding immune destruction
unlimited replicative potential (maintain the length of they telomeres)
tumour promoting inflammation
invasion and metastasis
angiogenesis (new blood vessel formation)
genome instability and mutation
evasion of cell death
reprogramming energy metabolism


What are the two emerging hallmarks of cancer?

reprogramming energy metabolism and avoiding immune destruction


what are the two enabling hallmarks of cancer?

tumour-promoting inflammation and genome instability and mutation


what is the difference between benign and malignant tumours?

- remains encapsulated
- non-invasive
- no metastasis
- usually not life-threatening
- non-encapsulated
- invasive and metastasises
- life-threatening
- fast growth
- non-differentiated


what are the differences between normal and cancer cells?

normal cells:
- grow in monolayers
- contact inhibition
- flat, extended morphology
- cannot grow in low serum
- anchorage dependant
cancer cells:
- grows in piles called 'foci'
- no contact inhibition
- rounded morphology
- grows in low serum
- anchor independant


what is the name for an agent that causes cancer?



what is a mutagen?

an agent that causes a DNA alteration, mutation.
most carcinogens are mutagens.


why is cancer called the 'disease of ageing'

accumulation of many mutations over time results in cancer formations


what is a germline mutation

DNA alterations in the sperm and egg cells that are passed on to offspring. they can increase risk of cancer but never directly induce cancer


what is a somatic mutation

a mutation of the body cells (somatic cells) via DNA alterations. This is passed onto daughter cells.


what is clonal origin

all cancerous cells arise from a single cell with multiple mutations


what are the three key mechanisms affected by mutation that lead to cancer

cell proliferation, differentiation and apoptosis


what are proto-oncogenes?

normal genes that can be activated by mutation to be oncogenic


what is an oncogene? How do they cause cancer?

a gene mutated such that its protein product is produced in higher quantities or has increased activity and therefore acts in a dominant manner to initiate tumour formation.
an example includes an oncogene that produces a growth factor receptor with increased activity so is therefore constituently active and doesn't require a GF to send a signal to cells


what is a tumour suppressor gene? How can they cause cancer?

codes for proteins that play a role in inhibiting growth and tumour formation, promoting differentiation and triggering apoptosis.
Loss of growth inhibition occurs when mutations cause loss of function of the gene. Mutations are recessive.


what is haploinsufficiency?

one mutated allele can lead to cancer phenotype


how can environment influence cancer?

exposure to carcinogens.
first seen in 1775, increased nasal and scrotal cancer in chimney sweeps due to chronic exposure to soot.
UVB in sunlight can directly alter DNA by forming pyrimidine dimers and cause mutations.


how does reproduction influence cancer?

having children young decreases chance for breast cancer
sexually transmitted human papillomaviruses are involved in cervical cancers.
human herpesvirus type 8 is involved in Kaposi's sarcomas, linked to AIDS


what lifestyle factors can affect cancer risk?

diet and exercise, reproduction, environment, alcohol consumption, smoking


what is the main objective of current cancer treatment?

inhibit or eradicate metastasised cells, prevent proliferation, and kill cancer cells (cytostatic and cytotoxic effects)


what is the therapeutic index?

value of the difference between the minimum effective dose and the maximum tolerated dose (MTD). The larger the value the safer the drug.
most cancer treatments are given at the MTD