1a. Cancer Physiology Flashcards
What are the major differences between benign and malignant tumours ?
Benign:
- Cancerous cells do not invade surrounding tissues ( Do not metastasise)
- Usually encapsulated
- Can arise in any tissue
- Cells resemble those of original tissues
- Cells well differentiated
- Cells grow slowly
- Relatively harmless
Malignant:
- Capable of intravastion, arrest at distant
site and metastasis
- Cells poorly differentiated; Frequent cell division leading to fast growing cells
- Poor outcome to the patient
What is the most common classification of cancers?
Carcinoma
Where do carcinomas arise ?
Arising from cells of embryonic endoderm or ectoderm and cover external and internal body surfaces e.g lungs, breast, colon
Where do sarcomas arise ?
Embryonic mesoderm which is the supporting tissues of the body such as the bone, cartilage, fat, connective tissues and muscles
Where do lymphomas arise ?
Lymph node and tissues of the body’s immune cells
where do Leukaemia’s arise ?
Cancer of the immature white blood cells that grow in the bone marrow and accumulate in large numbers in the blood stream (circulating cancers)
List 5 causes of cancers
Tabacco Body weight Physical activity Diet Hormone Sunlight occupational carcinogens Infectious agents Medical treatments Pollution genetic factors
What are the early stage symptoms of cancers ?
Usually disease specific and often early stages display no symptoms
What are the symptoms of lung cancers ?
Cough haemoptysis (coughing up blood) Chest pain Breathlessness Tiredness Similar symptoms to congestive heart failure
What are the symptoms of pancreatic cancer ?
Weight loss
Stomach or back pain
Jaundice
Development of diabetes
What are the common symptoms of breast cancer ?
Lump of thickening Changes in breast size Discharge Bleeding Weight loss
What are the cancer gene mutations that can lead to cancer ?
1) Proto-oncogenes: Loss in function can increase growth of cells as this gene encodes aspects of the signalling pathway that regulates proliferation
2) Tumour suppressor genes: Loss of function leads to dysregulation of cell cycle control. protein degradation and cell adhesion and motility
3) DNA repair enzymes: Loss in function attenuates repair process and genomic integrity
What makes a cell metastatic ?
Development of genetic mutations over time
This can be caused by:
1) Mutagenic initiation
2) Selected mutations
3) Epigenetic alterations
What is mutagenic initiation ?
Mutations caused by:
- Chemicals, radiation, viruses, spontaneous changes
- Increased genome instability, positively selected
Give examples of selected mutations
Missense, nonsense, silent or chromosomal alterations
