oncology Flashcards
what are oncogenes?
needed for normal growth and are tightly controlled but the control can be lose with mutation
can be expressed by some viruses
what are tumour supressor genes?
stop cells from proliferating out of control
how are tumour supressor genes function lost?
by both copies being mutated / deleted / silenced
how many mutations need to be acuumulated to initiate a tumour?
10-12
what are the 6 hallmarks of cancer?
1) sustaining proliferative signalling
2) evading growth suppressors
3) resisting cell death
4) enabling replicative immortality
5) inducing angiogenesis
6) activating invasion and metastasis
why is sustaining proliferative signalling useful? and how does it happen?
can become self sufficient at growth
- endogenous growth factors
- mutated growth factor receptors so always turned on
- over express growth factors so respond to tiny amounts
- mutate intracellular pathway so always activated
what is the therapy target for sustaining proliferative signalling?
EGFR inhibitors
how do they evade growth suppressors?
resist tumour suppressor genes -
- Rb controls cell cycle progression
- p53 halts cycle if not normal
what is the therapy target for evading growth supressors?
cyclin dependant kinase inhibitors
how do cells resist cell death?
-avoid caspase cascade
- extrinsic pathway via death receptors
- intrinsic pathway from DNA damage
- resistance to anti-cancer drugs
what is the therapy target for resisting cell death?
Pro-apoptic BH3 mimetics
how do cells enable replicative immortality?
telomerase adds telomeres on
what is the therapy target for replicative immortality?
telomerase inhibitor
how does a tumour induce angiogenesis?
secretes vascular endothelial growth factor (VEGF)
what is the therapy target for angiogenesis?
VEGF inhibitor
what is the therapy target for invasion and mets?
HGF / c-met inhibitor
What are the 4 emerging hallmarks?
1) deregulating cellular energetics / reprogramming energy metabolism
2) evading immune destruction
3) genome instability and mutation
4) tumour promoting inflammation
What is the therapy target for deregulating cellular energetics?
aerobic glycolysis inhibitors
what is the therapy target for evading immune destruction?
immune activating anti-CTLA4 mAb
what is the therapy target for genome instability?
PARP inhibitors
what is the therapy target for tumour promoting inflammation?
anti-infl drugs
how may inflammation promote tumours?
provides growth factors, cytokines and immuno suppression
what are the characteristics of a feline injection site sarcoma?
- previous FeLV or rabies vax
- at site of inj
- non painful
- firm
- fixed
- locally invasive
- cystic
- fast growing
How do you diagnose a feline injection site sarcoma?
incisional biopsy
what is the 321 rule with feline injection site sarcomas?
its likely to be one if its over 3 months since a vax, over 2 cm and has increased in size 1 month post vax
why is cytology not useful at diagnosing feline infection site sarcomas?
- as cystic so may just take cystic fluid so not representative
- cant grade it
- if under a month since vax then inflammation may still become neoplastic
why would you not do an excisional biopsy to diagnose feline injection site sarcoma?
- no long term benefit
- can affect prognosis as with second curative surgery may have mets, inflammation and fibrosis, seeding through tissue planes and will need larger margins, altered anatomy, less tissue to close with
how do you treat feline injection site sarcomas?
- radical 1st surgery with 3-5 cm margins
- adjuvant radiation for 3-4 w
how can you avoid feline injection site sarcoma?
dont over vacc
dont repeatedly vaccinate in the same location
put vax in distal rear limb
use adjuvant free vax
what can cytology tell you / not tell you?
tell you - cell type, morphology
not - architecture, mitotic index, invasion, vasculature / lymph
What can histopathology tell you?
cell type morphology tissue architecture mitotic index vasculature / lymph necrosis
what are the 3 main categories ?
epithelial
mesenchymal
round cell
what is an epithelial tumour called?
carcinoma
what is a mesenchymal tumour called?
sarcoma
what information is used to grade a tumour?
mitotic index cellular differenatiation invasion of surrounding tissues vascular / lymph necrosis
how is a tumour stages?
TNM
- T = primary tumour size (T1-3)
- N = regional LN (N0 = no mets , N1 = mets)
- M = distant mets (M0=none , M1=some)
what is paraneoplastic syndrome?
systemic effects of a tumour, occuring at sites distant to the tumour due to hormones, cytokines or enzymes from the tumour
what can high calcium cause?
PU/PD anorexia depression weakness bradycardia
What can low glucose cause?
weak
collapse
seizures
What can viscose bloody cause?
neuro signs
retinal detachement
What is neoplasia?
a monoclonal, uncontrolled proliferation of cells that continues in the absence of the inciting cause
what is seen grossly with a benign tumour?
grow by expansion slow growth well demarcated smooth outline CT capsule freely mobile homogenous cut surface little haemorrhage or necrosis surgical removal easy no recurrence if fully excised no metastasis
what is seen grossly with a malignant tumour?
grow by invasion ulcerative on surface not encapsulated not mobile on palpation necrosis and haemorrhage removal difficult often recurs mets
what is seen micrscopically with benign tumours?
similar to tissue of origin well organised can be functioning doesnt breach capsule few / no mitotic cells
what is seen microscopically with maliganant tumours?
loss of cohesiveness and structure no capsule increased mitotic index variable cell size +shape = pleomorphism variable nuclei size +shape = anisokaryosis increased nucleus : cytoplasm ratio prominent nuclei multinucleated syncytia necrosis fibrosis inflammtion
what is a benign surface and gut ep tumour?
papilloma
benign glandular ep?
adenoma
malignant surface and gut ep
carcinoma
malignant glandular ep
adenocarcinoma
fibrous benign
fibroma
bone benign
osteoma
cartilage benign
chondroma
adipose benign
lipoma