Pathology - neoplasia Flashcards
What is neoplasia?
- New growth
- Not in response to a stimulus
- Can be benign, pre-malignant or malignant
What are some examples (pathology terms) of pre-cursor lesions?
Dysplasia, metaplasia and even hyperplasia
What is metaplasia and what can it lead to?
- Reversible change from one mature cell type to another mature cell type
- Metaplastic tissue is an at risk site for the development of cancer
What is a common metaplastic response to a noxious stimulus?
- Squamous metaplasia
- Squamous epithelium covers the skin and is very resistant to noxious stimuli so squamous metaplasia is therefore commonly encountered in response to injury e.g. the lung bronchial epithelium is not good with thermal injury so turns to squamous epithelium
When might squamous metaplasia occur in the bladder?
Usually transitional epithelium in the bladder, catheter (for example) creates inflammation so causes squamous metaplasia to occur
What is dysplasia?
- Disordered growth
- Growth is not in response to a stimulus
- No invasion i.e. growth beyond BM
- Often graded - low grade most normal, high grade most abnormal and closest to becoming cancer
What is carcinoma in situ?
- Dysplasia affecting the whole of the epithelium
- Last stage before becoming invasive
What are Weinberg’s hallmarks of cancer?
- Increased growth signals
- Remove growth suppression
- Achieve apoptosis
- Achieve immortality
- Become invasive
- Make your own blood supply (angiogenesis)
- Loss of DNA repair
- Avoid immune detection
What are some examples of autosomal dominant genes that cause cancer?
- RB mutation - retinoblastoma in children
- APC gene - familial adenomatous polyposis (FAP)
What is the double hit hypothesis?
- One working gene is enough, two faulty copies to have a functional problem
- Those who have inherited one faulty copy are at an increased risk
What do initiators do?
Long lasting genetic damage, no sufficient to cause cancer, must be followed by a promotor
What do promoters do?
Require initiators to have caused damage, time period can vary after initiation
What cancer types is smoking associated with?
Lung cancer (SCLC), head and neck cancers, bladder cancers and cervical cancer
What type of cancer are aflatoxins associated with and where can they be found?
- Liver cancers
- Found in fungus on peanuts
- Associated with p53 mutations
What type of cancer are beta naphthylines associated with and where can they be found?
- Bladder cancers
- Found in dye
What is xeroderma pigmentosa caused by?
Genetic defect in NER (nucleotide excision repair) and patients suffer from numerous skin cancers
What type of cancers do radiation increase the risk of?
Leukaemias and thyroid cancers
What tumours are associated with EBV?
Burkitt lymphoma, B-cell lymphomas, Hodgkin lymphomas, nasopharyngeal carcinoma
Why can obesity cause cancer?
- Hyperplasia in endometrium
- Cholesterol analogous to oestrogen
- Increases risk of renal cell carcinoma
What are the 3 types of growth receptor involved in cancer growth?
- Receptors with intrinsic tyrosine kinase activity
- 7 transmembrane G protein-coupled receptors
- Receptors without intrinsic tyrosine kinase activity
What is Myc protein?
A nuclear transcription factor that promotes growth - DNA replication etc.
What types of cancer is a Myc protein mutation seen in?
- Common in lymphoma, neuroblastoma, SCLC
- Burkitt lymphoma t(8;14) - Myc translocation
What is the most commonly mutated kinase in cancer?
- PI3K
- Targeted in haematological malignancies