Behaviour of Tumours Flashcards
Describe what invasion means in terms of a malignant tumour
- Invades adjacent normal tissue
- Destroys normal tissue
- Local disease
Describe what metastasis means in terms of a malignant tumour
- Spreads from site of origin to distant sites
- Forms new tumours in these areas
- Systemic disease
What types of cancers are most likely to metastasise?
- 1/2 of all cancer patients
- Majority of lung cancer patients
- 1/3 of breast cancer patients
- Almost no basal cell carcinoma patients
What are the characteristics of invasion?
- Increased motility
- Decreased adhesion
- Production of proteolytic enzymes
- Mechanical pressure
What happens when a Cadherin mutates?
Mutation of E-Cadherin leads to loss of cell-cell adhesion and contact inhibition
What happens when an Integrin mutates?
Changes in integrin expression lead to decreased cell-matrix adhesion
What is the difference between epithelial cell connection and mesenchymal cell connection?
- E= tightly connected, polarised and tethered
- M= loosely connected, able to migrate
- In cancer epithelial cells gain mesenchymal properties allowing them to invade/migrate
Name a proteolytic enzymes which degrades extracellular matrix. What does it degrade specifically?
- Matrix Metalloproteinases
- Collagen
Name 3 proteolytic enzymes and what they degrade
- Interstitial Collagenases= Collagen types I, II, III
- Gelatinases=Collagen types IV, gelatin
- Stomolysins=Collagen type IV, proteoglycans
How can Proteolytic enzymes aid in cancer formation?
- Increase in matrix Metalloproteinases
- Cancer favours ECM breakdown
- Decrease in tissue inhibitors of Metalloproteinases
What is mechanical pressure?
- Uncontrolled proliferation forms mass
- Pressure occludes vessels
- Pressure atrophy
- Spread along lines of least resistance
What are the routes of metastasis?
- Lymphatic = Distant or local lymph nodes
- Blood = Liver, lungs, bone, brain
- Transcoelomic = Across peritoneal, pleural, pericardial cavities or CSF
- Implantation = Spillage of tumour during biopsy/ surgery
Give examples of patterns of metastasis
- Carcinomas= lymphatic spread
- Sarcomas= blood spread
- Bone metastases= lytic (lung) or sclerotic (prostate), breast, kidney, thyroid
- Transcoelomic= Ovarian
- Brain& adrenal= Lung
What does staging mean?
How advanced is the tumour?
Has the cancer spread and if so what is the extent of the spread
What does grading mean?
How aggressive is the tumour?
How different does it look from tissue of origin
What are the stages of cancer progression?
1) Pre-invasive
2) Early tumour
3) Locally advanced
4) Metastases
5) Death
What are tumours staged using?
TMN T= tumour M= metastases N= nodes Each organ has an individual TMN system
Describe TMN staging
T= Size +/- extent of primary tumour M= Presence and extent of distant metastases N= Presence and number or lymph node metastases
What are the T stages of TMN staging
Tis= in situ disease T1= 7cm (invasion of fat/adjacent structures)
What are the N and M stages of the TMN staging?
N0= no nodes N1= Ipsilateral nodes N2= > node involvement M0= no distant metastases M1= distant metastases
What do stages 0-IV contain (as in TNM)
0= Tis 1= T1, N0, M0 = Surgery only 2= T1-2, N1 or T3 = Surgery & RT 3= T(any), N2 or T4= Surgery & chemo 4= T(any), N(any), M1 = chemo
Describe Duke staging
-For Colorectal cancer
A= Invades into but not through bowel wall, >90% 5 year survival
B= Invades through bowel wall but no lymph metastases, 70% 5 year survival
C= Local lymph nodes involved 30% 5 survival
D= Distant metastases 5-10% 5 year survival
