Intro to cancer Flashcards
What is cancer?
- Cancer is a group of diseases
- Charachterised by abnormal cell growth through which cells may acquire potential to disperse (metastasise) from site of origin (primary tumour) to other sites in body(secondary tumours)
- Tumour growth id dependent upon delivery of nutrients and oxygen via incd vascular supply (angiogeneisis)
What are the different types of Tumour?
- Benign
- Malignant
What are benign tumours?
- Cells do not invade surrounding tissue - Do not metastasise
- Usually encapsualted - Restrains invasive capacity
- Can arise in any tissues; cells resemble those original tissue
- Cells well differentiated, slow growing
- For the most part, relatively harmless
What are Malignant tumours?
- Capable of intravasation, arrest at distant site and metastasis
- 85% carcinomas (epithelial cells), most others are sarcomas (Mesenchymal–connective tissue, fat, bone, etc)
- 3% are leukaemias and lymphomas - liquid tumours
- Cells poorly differentiated; Freq cell divisions–>Fast growing
- Leads to poor patient outcomes
What are the classifications of cancer pathology?
Carcinoma
* Most common type of cancer
* Arising from cells of embryonic endoderm or ectoderm
* Cover external and internal body surfacese.g. lung, breast, colon
Sarcoma
* Cancer arising from cells of embryonic mesoderm
* The supporting cells of body, bone, cartilage, fat, connective tissue and muscle
Lymphoma
* Cancer that arises in lymph nodes and tissues of bodies immmune system
Leukaemia
* Cancer of the immature white blood cells that grow in the bone marrow and accumulate in large numbers in blood stream
What are the causes of cancer?
- Tobacco
- Body weight
- Physical activity
- Diet
- Hormones
- Sunlight (UV)
- Occupational carcinogens
- Infectious agents (Viruses, Bacteria)
- Medical treatment
- Pollution
- Genetic factors
What are symptoms of cancer?
- Disease specific
- Often no symptoms in the early stages; but metastasis is early event
Lung cancer
* Cough haemoptysis (Coughing blood), chest pain, breathlessness and tiredness
Pancreatic cancer
* Weight loss, stomach or back pain, jaundice, development of diabetes
Breast cancer
* Lump or thickening (90% of such abnormalities are benign), change in breast size, discharge, bleeding, weight loss
What are mutations of cancer genes?
- Disruption of processes that control growth, location and mortality of cells contribute to development of tumours
-
Proto-oncogenes
* Encode aspects of signalling pathways that regulate proliferation
* Loss of function inc growth
2.Tumour suppressor genes
* Loss of function leads to dysregulation of cell cycle control, protein degredation, cell adhesion and motility
3.DNA repair enzymes
* Loss of function attenuates repair processes and genomic integrity
Explain diagram of cancer mutations
What makes a cell metastatic?
- Genetic mutations: Normal cell transforms into a cancer cell by accural of multiple genetic mutations over time
-
Mutagenic initiation
* Chemicals, radiation, viruses, spontaneous changes
* Incd Genome instability, positively selected -
Epigenetic alterations
* Acetuylation, methylation
What is Metastasis?
(The cascade) part 1
1.Migration – Cells move away from primary site and invade neighbouring tissue
2.Intravasation – Cells transmigrate across vessel wall barrier and enter circulation
* Enhanced by chronic inf, EC integrity loss, inc permeability
3.Survival – New microenvironment, shear forces from blood flow
* Only 1-4% of circulation tumour cells complete metastatic cascade
* Heterogenous pop of cells
* Heterotypic interactions with platelets - pro-metastatic role
* Selectins - Expressed by platelets and recognise carbohydrate moiety on cancer cells
* (Attach to cancer cells and protect them from immune responses and physical stress of blood vessel)
What is Metastasis?
(The cascade) part 2
4.Arrest at distant site - Cells have to avoid hostile blood or lymphatic flow forces and subsequently adhere stably to endothelial lining of target organs
* Endothelial fitness and crosstalk with CTCs might define final metastatic outcome
5.Extravasation - Cells transmigrate across vessel wall barrier and leave circulation
* Enhanced by chronic inf, EC integrity lost, incd permeability
6.Growth of secondary tumour
* Important role of angiogenesis
Explain the cascasde (diagram)
What are the hallmarks of cancer?
- Lifecycle of cancer?
- Sustaining proliferate signalling
- Evading growth suppressors
- Activating invasion and metastasis
- Enabling replicative immortality
- Inducing angiogenesis
- Resisting cell death
What are the emerging Hallmarks and enabling charchteristics of cancer?
Emerging Hallmarks
* Avoiding immune destruction
* Deregulating Cellular energetics
Enabling Characteristics
* Tumour-promoting inflammation
* Genome instability and mutation
Compare normal vs tumour blood vessels
(Diagram)
