Theme 5: Neoplasia - Part 2 Flashcards
What are the four types of tissue a tumour can arise from?
- connective tissue
- epithelial tissue
- muscle tissue
- nervous tissue
How do we classify benign epithelial tumours?
- Either glandular or secretory
- glandular- adenoma
not secretory - papilloma - Tumour then further identified - cell type of origin e.g squamous cell papilloma, thyroid adenoma
How do we classify malignant epithelial tumours?
- Carcinoma - non glandular epithelium e.g basal cell carcinoma
OR - Adenocarcinoma - glandular epithelium e.g colorectal adenocarcinoma
What is carcinoma “in-situ”?
- abnormal cells but in the correct space- they then invade and become carcinoma
- preceded by dysplasia (disordered maturation and nuclear changes)
- not invaded through basement membrane
What are the prefixes of tumours that arise in the following tissues:
- Smooth muscle
- Skeletal muscle
- Adipose
- Blood vessel
- Bone
- Cartilage
- Fibrous
- Leiomyo-
- Rhabdomyo
- Lipo-
- Angio-
- Osteo-
- Chondro-
- Fibro-
What are malignant mesenchymal tumours called?
Sarcomas
e.g malignant tumour arising from fat wound be called liposarcoma
What is a melanocyte?
melanin - producing cell
responsible for skin colour
What is a melanocytes naevus?
mole
What is a mesothelioma?
arises from the pleural cavity - from the cells that line the pleura. Always malignant
What are the 4 types of CNS tumours?
- Meningioma - arise from meninges (membranes that cover the brain)
- Glioma - from glial cells
- Pituitary tumours
- Neurones
What are germ cell tumours and how are they classified?
- arise from germ cells
- either found in gonads (ovary and testis) or midline
- nonclamature based on gonad - seminoma (testis) or dysgerminoma (ovary)
- nonclamature based on differentiation (what tissues are the cells resembling) - yolk sac tumour, teratoma, choriocarcinoma embryonal carcinoma
What is a teratoma?
A mixed germ cell tumour (lots of different cell types) and is malignant
What are blastomas? give examples
cancerous growth developing in foetus or child
-retinoblastoma, nephroblastoma (“Wilm’s tumour), neuroblastoma, hepatoblastoma
What are the 3 types of haematological malignancies?
- leukaemia - marrow/blood
- lymphoma - lymph nodes/ other solid tissues
- myeloma - plasma cells
What is a hamartoma?
non cancerous (benign) tumour made of an abnormal mixture of normal tissue and cells from the area in which it grows
What is a cyst?
A fluid filled space lined by epithelium
many causes, can be neoplastic
What would a benign tumour of blood vessels and fat be called?
vessels = angio
fat = lip
benign = -oma
= angiolipoma
What would a malignant tumour with epithelial and stromal components be called?
malignant epithelial - carcinoma
malignant stromal - sarcoma
= carcinosarcoma
What is the difference between a primary and secondary tumour?
Primary- at site of origin
Secondary - metastatic
What is a carcinogen?
Any agent that will statistically significantly increase your risk of getting cancer
What is a “complete” carcinongen?
can initiate and promote
(chemically modifies DNA, induces proliferation and DNA replication) e.g UV light
-we need initiation and promotion
What are the 5 categories of carcinogens?
- Chemicals
- Infectious agents e.g HPV
- Radiation
- Minerals e.g asbestos, heavy metals
- Physiological e.g oestrogen, androgens, obesity
What do promotors do?
- stimulate DNA replication for mutation fixation
- stimulate clonal expansion of mutated cells, which enables accumulation of further mutations
What are the two consequences of mutations?
- Gain of function (activation of protocol-oncogenes)
2. Loss of function (inactivation of tumour suppressor genes)
How do we inactive a TSG?
Methylation of CpG island
What are two ways carcinogens can activate metabolism?
- direct acting - free radicals, nitrosamines, UV light, ionising radiation
- pro carcinogens - require enzymatic activation before reacting with DNA e.g aromatic amines
What is the process from carcinogen exposure to cancer?
- Carcinogen exposure
- Metabolic activation
- DNA damage
(4. DNA repair?) - DNA replication
- Mutation
- Progression
- Cancer
What defences do we have against carcinogens?
- antioxidants (fruit and veg): act against free radicals
- liver: detoxify and excrete carcinogens
- DNA repair process
- immune response: identifies abnormal cells
- apoptosis: destroys abnormal cells
How can alcohol cause cancer?
- linked to oral, oesophageal, bowel and liver cancer
- converted into acetaldehyde - can cause DNA damage
- increases levels of oestrogen and testosterone
- increases uptake in carcinogenic chemicals into cells within the upper GI
- reduced levels of folate, needed for accurate DNA replication
- can kill surface epithelium leading to unscheduled proliferation
How many compounds with confirmed carcinogenic activity are found in cigarettes? give examples
70:
- acetaldehyde
- 1,3-butadiene
- benzene
- aromatic amines
What factors increase your levels of oestrogen?
- alcohol consumption
- oral contraception
- hormone replacement therapy
- age of 1st pregnancy > 30 yrs
- early menarche (1st period)
- late menopause
- post menopausal obesity
how is chronic inflammation a cause of cancer?
- DNA damage from free radicals released by immune cells (initiation)
- Growth factor induced cell division to repair tissue damage - promotion
- growth factors secreted also encourage growth of abnormal cells
What are the 4 main environmental or behavioural factors that are attribituble to cancer deaths?
- diet
- tobacco
- infection
- reprod. behaviour
What does sebaceous mean?
secrete an oily/ waxy matter called sebum
What would a benign tumour of smooth muscle be called?
Leiomyoma
What are 4 types of DNA repair mechanisms?
- base excision repair
- mismatch repair
- nucleotide excision repair
- recombinational repair
What is a benign tumour of glandular epithelium called?
adenoma
What is a malignant tumour of cartilage called?
chondrosarcoma
What is a malignant tumour of placental tissue called?
Choriocarcinoma
What is a carcinoma?
Any agent that significantly increases the risk of developing cancer
What is an initiator carcinogen?
any agent that will chemically modify DNA
What is HNPCC and which cancer does this predispose you to?
Hereditary non-polyposis colorectal cancer
predisposes to colorectal cancer
In Xeroderma pigmentosa, there is a defect in which repair mechanism?
Nucleotide excision repair
XP - genetic disorder where there is a decreased ability to repair DNA damage such as that caused by UV light
Why if a group of people are all exposed to the same carcinogen, do they not get cancer?
- different metabolic activation (cytochrome p450s)
- differences in DNA repair mechanisms
- differences in detoxification and excretion
