CE L1 Introduciton Flashcards
Why is cancer so hard to treat?
3
It’s self
Not diagnosed until late (few symptoms)
Need to eradicate every single cell
Cancer is cells growing ….. and …..
too fast and too much
Cancer is more common in what type of cells?
Why?
Cells with a high turnover
- most mutations are passed on during cell division
When do we actually want cells to divide and proliferate? (2)
Growth and repair
What is cancer?
Unregulated growth of abnormal cells, often at inappropriate locations
What is cancer caused by?
DNA damage - proteins controlling the function of cells are changed
Cancer cells appear ….
immature - therefore cannot carry out their function
What normally kills you in cancer?
Not the tumour itself but the lack of normal funciton
What is missing in cancer that would normally prevent cells from keeping growing once they are touching other cells?
Contact inhibition
Tumours are classified according to
tissue of origin
Sarcomas Carcinomas Leukaemias Adenocarcinomas arise from...
Sarcomas - connecting tissue/muscle
Carcinomas - epithlial cells
Leukaemia - blood cell
Adenocarcinomas - glandular tissue
Properties of benign tumour (4)
- Resembles normal cells
- Localized
- Surrounded by fibrous capsule
- Usually require little treatment (e.g. warts) - Surgical removal if apprprate
Genetic make-up can predispose you to environmental shock e.g.
smoking - some people don’t develop cancer even after many years
Properties of malignant tumours: (6)
- less well differentiated
- grow and divide rapidly
- high nucleus to cytoplasm ratio
- invade surrounding tissue
- more difficult to treat as less defined
- enter circulation and metastasis
Properties of malignant tumours: (6)
- less well differentiated
- grow and divide rapidly
- high nucleus to cytoplasm ratio
- invade surrounding tissue
- more difficult to treat as less defined
- Metastasis
Define metastasis
entering circulating and seeding at a different site
Genetic predisposition examples (2)
- Li-frumeni syndrome
2. Chronic myloid leukemia (CML)
What happens in Li-frumeni syndrome?
inherited mutation of one p53 gene. Normally functions as a tumour suppressor. Wild type then mutates and cancers form in childhood
What happens genetically in CML
chromosomal translocation
Environemental stressors examples (4)
Animal fat in prostate cancer
UV
Radium and oral cancer
Tabacco
Many tumour cells have constitutively active pathways thus producing their own….
growth factors
What are proto-oncogenes?
sds
What are proto-oncogenes?
What happens to them?
genes whose normal function is to control cell growth. Converted into oncogenes by a GAIN OF FUNCTION mutation.
3 e.g. of gain of funciton mutations
point mutation - always active
gene amplification - more protein
chromosomal translocation
What are oncogenes?
Gene which encodes a protein able to transform cells - derived from proto-oncogene
What are tumour suppressor genes (3 functions)
Gene which restrain cell growth, promote cell death and promote DNA repair
…………………. of tumour suppressor genes leads to unregulated cell growth of damaged cells
LOSS OF FUNCTION
Tumour suppressor genes are dominant or recessive?
Recessive - so both copies must be lost
How does hereditary predisposition with tumour suppressor genes work?
You inherit one mutant and later in life the other mutates
What is epigenetics?
Gene regulation:
Modifications to genomic and chromatin components and structure - alter gene transcription and hence protein expression
What things does epigentics wrok with (3)?
Histom modificate
methylation
miRNA
How many changes have taken place to make cancer
3-7 ( cells must survive each one to acquire the next, on different survival pathways)
How many changes have taken place to make cancer
3-7 ( cells must survive each one to acquire the next, on different survival pathways)
Benign tissue surrounding tumour frequently contains …
all but one of these mutations
Will we cure cancer in the future?
more likely to transform it into a long term chronic disease what pt can live with
Each cell in the cancer is….
a clone of a single cell
Cells taken from the outside of a tumour do/don’t grow into cancer when implanted?
Don’t - indicating stem cells?
Once metastasis has occurred prognosis is
poor
In order for cells to break off and metastasise what must happen?
breakdown and degradation of the basal lamina (release of MMP and invadopodia)
What is a transformed cell?
Survives longer than it should but is not full on caner
