Pathology - Neoplasia Flashcards
What is the pathological definition of cancer?
Uncontrolled cell proliferation and growth that can invade other tissues
What is a tumour?
A growth
What is a neoplasm?
A new growth which is not in response to any stimulus
What does malignant mean?
Metatastic potential
Invaded through the basement membrane
What dies metastases mean?
Spread to other sites through blood or lymphatics
What is dysplasia?
Disordered growth
No invasion of basement membrane
What is carcinoma in-situ?
Dysplasia affecting the whole of the epithelium
Still no invasion at this point - last stage before invasion
What is metaplasia?
Change form one the of mature epithelium to another
Usually in response to injury
Why are sites of metaplasia associated with cancer?
The epithelium is changing and constantly being damaged, and so is unstable
This makes it more likely to undergo dysplasia
How is hyperplasia associated with cancer?
Can become autonomous and no longer require a stimulus (uncontrolled growth)
Why are obese individuals more prone to cancer (e.g. endometrial cancer)?
Structure of steroid hormones is similar to cholesterol
Although women stop producing oestrogen post-menopause, cholesterol can still act as a stimulus for endometrial growth
if growth becomes permanently switched on, cancer risk increases
What factors can contribute to cancer?
Inherited predisposition Chemicals Radiation Infections Inflammation Lifestyle factors
What is the double hit hypothesis?
One working gene is enough
Two faulty copies will result in functional problem
Why are people with an inherited predisposition more t risk?
If you have already inherited one faulty copy of a gene, you will be at increased risk (“one hit left”)
What chemicals can cause cancer?
Smoking carcinogens = Lung, bladder, head and neck, cervical (alongside HPV)
Aflatoxin (fungus on peanuts) = Liver
Beta-naphthylamine (chemical dyes) = Bladder
Nitrosamines (food preservatives)
Arsenic
How does UV radiation cause cancer?
UVB
Causes DNA damage. Initially, this can be repaired, but on repeat exposure the mechanisms are overwhelmed
What kinds of radiation exposure can cause cancer?
UV
Atomic Bombs (high incidence of leukaemia in Japan)
X-Ray/CT
Which method of imaging gives highest risk of radiation exposure?
CT
More susceptible to leukaemias and thyroid cancers
Which viruses are know to cause cancers?
HPV = Cervical cancer, head and neck cancers EBV = Burkitt-lymphoma, B-cell lymphomas, Hodgkin lymphoma, Nasopharyngeal carcinoma
How does chronic inflammation cause cancer?
Must be very long term and intense
Causes many lymphomas due to constant lymphocyte reproduction - this may lead to errors
Other tumours can be caused as the tissue is replicating so often it becomes unstable
Often in the context of metaplastic change (e.g. permeant catheterisation, chronic gastritis etc.)
What are the four main groups of cancer development?
Oncogenes - Promote growth
Destroy tumour suppressors - Avoid inhibition of growth
Evade apoptosis - Avoid death
Spell checkers - Turned off by malignant cells. Allows accumulation of mutation and allows these to evade apoptosis
What is MMP (matrix metalloproteinases)?
Substances produced by malignant cells to digest connective tissue
What is angiogenesis?
The ability of tumours to create their own blood supply
Tumours often have mutations which allow them to produce proteins encouraging new vessel growth
e.g. vascular endothelial growth factor, platelet derived growth factor
What are the three stages of cancer development?
Initiation
Promotion
Persistance
