Cancer and Neoplasia Flashcards
(85 cards)
1
Q
What is a tumour?
A
Any abnormal swelling - this includes inflammation, neoplasms, hypertrophy and hyperplasia
2
Q
What is a neoplasm?
A
A lesion resulting from the autonomous abnormal growth of cells, which persists after the initiating stimulus has been removed.
3
Q
What percentage of UK deaths can be attributed to neoplasia?
A
20%
4
Q
What does a neoplasm consist of?
A
Neoplastic cells and stroma
5
Q
Give 3 characteristics of neoplastic cells
A
- Derived from nucleated cells (usually monoclonal)
- Have a growth pattern related to the parent cell
- Have synthetic activity related to the parent cell (e.g. collagen, mucin, keratin, hormones)
6
Q
What is the stroma of a neoplasm and what is its role?
A
The stroma supports the neoplasm; it consists of a connective tissue framework providing support and nutrition and its growth is supported by the neoplasm.
7
Q
How large can a neoplasm grow without recruiting a blood supply?
A
About 2mm
8
Q
Why does central necrosis sometimes occur in large vascularised tumours?
A
The tumour outgrows its blood supply and the cells in the centre die off as they are too far from the blood supply.
9
Q
What are the two methods of classification used when classifying neoplasms?
A
Behavioural - e.g. benign/malignant/borderline
Histogenetic - cell of origin/what tissue is present
10
Q
Give 7 characteristics of benign neoplasms
A
- Localised
- Non-invasive
- Slow growth rate
- Low mitotic activity
- Close resemblance to normal tissue
- Circumscribed/encapsulated
- Necrosis and ulceration are rare
11
Q
Give 4 ways in which benign neoplasms can cause morbidity and mortality
A
- Putting pressure on adjacent structures and obstructing hollow structures
- Over-production of hormones - benign neoplasms can retain synthetic properties but are autonomous and therefore unregulated
- Transformation to malignant neoplasm
- Anxiety
12
Q
Give 10 characteristics of malignant neoplasms
A
- Invasive
- Metastatic (may not have actually spread, but will have the potential to do so)
- Rapid growth rate
- High mitotic activity
- Variable resemblance to normal tissue
- Poorly defined/irregular border due to invasion of surrounding normal tissues –> margin between neoplasm and surrounding tissue unclear
- Hyperchromatic nuclei
- Necrosis and ulceration common
- “Crab-like” cut surface
13
Q
Give 6 ways in which malignant neoplasms caused morbidity and mortality
A
- Destruction of adjacent tissue
- Metastases
- Blood loss from ulcers
- Obstruction of flow
- Hormone production
- Anxiety and pain (although cancer is usually advanced by the time pain is felt)
14
Q
What is a papilloma?
A
A benign tumour of non-glandular, non-secretory epithelium. Prefixed with cell type of origin.
15
Q
What is an adenoma?
A
A benign tumour of glandular/secretory epithelium. Prefixed with cell type of origin.
16
Q
What is a carcinoma?
A
A malignant neoplasm of epithelial cells
17
Q
What is a sarcoma?
A
A malignant neoplasm of connective tissue
18
Q
What is an anaplastic tumour?
A
A tumour where the cell type of origin is unknown
19
Q
What is carcinogenesis?
A
The transformation of normal cells to malignant neoplastic cells through permanent genetic alterations/mutations.
20
Q
What is oncogenesis?
A
The transformation of normal cells to benign or malignant neoplastic cells
21
Q
What does ‘carcinogenic’ mean?
A
Cancer causing
22
Q
What does ‘oncogenic’ mean?
A
Tumour causing
23
Q
What is a mutagen?
A
An agent that acts on DNA
24
Q
Approximately what percentage of cancer risk is due to environmental factors?
A
85%
25
How was it discovered that hepatitis causes liver cancer?
High incidence of liver cancer was noted in areas with a high incidence of hepatitis B and C.
26
What is thought to be the reason behind the high incidence of oesophageal cancer in Turkey?
Food/drink being too hot, resulting in repeated thermal injury to the oesophagus, leading to cancer.
27
In which industries has there been a high incidence of bladder cancer among workers?
Aniline dye and rubber industries
28
Roughly how many deaths per year in the UK are caused by lung cancer?
About 35,000
29
How did Kent micronite filters manage to make smoking even more dangerous?
They contained asbestos
30
Why was there an increased incidence of scrotal cancer in male chimney sweeps?
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic. Chimney sweeps used to carry a rag to wipe themselves down with, which was kept in the pocket, in close proximity to the scrotum.
31
Thorotrast is a colloidal suspension of thorium used as a radiographic contrast medium from 1930-1950. How did it cause cancer?
Thorium is irreversibly ingested by phagocytes and has a long half-life. E.g. if it is ingested by Kupffer cells, it can turn the liver radioactive.
32
Why did the Chernobyl disaster of 1986 cause a massively increased incidence of cancer in Ukrainian children?
Radioactive iodine was released into the atmosphere; iodine is used to synthesise thyroxine so radioactive iodine was being taken up into their thyroids.
33
Give two reasons why animal experimentation may not always be relevant to human experience.
1. Animals may metabolise agents differently to humans, so agents that cause cancer in animals may not cause cancer in humans and vice versa.
2. The laboratory environment that the animals are in is vastly different to the normal human environment.
34
Give 4 classes of carcinogens
1. Chemical
2. Viral
3. Ionising/non-ionising radiation
4. Hormones/parasites/mycotoxins
35
What is a pro-carcinogen?
A chemical agent that is metabolised into a different chemical, which in turn causes cancer (the metabolite is called an 'ultimate carcinogen')
36
Why might a pro-carcinogen only result in cancer in certain tissues?
Because the enzyme required to metabolise the pro-carcinogen compound may only be found in certain tissues
37
How does alcohol increase the risk of oropharyngeal cancer specifically?
It increases the oropharyngeal cells' permeability to other carcinogens
38
How does alcohol increase the risk of breast cancer specifically?
Ethanol increases oestrogen levels - many breast cancers are oestrogen-receptor positive.
39
How does alcohol cause cancer in general?
It is metabolised into acetaldehyde, which is mutagenic.
40
Epstein-Barr virus increases the risk of which 5 types of cancer?
1. Nasopharyngeal carcinoma
2. Burkitt lymphoma
3. Hodgkin disease
4. B- and T-cell lymphomas
5. Leiomyosarcoma
41
Human papillomavirus increases the chance of developing squamous cell carcinomas in which six areas?
1. Oropharynx
2. Cervix
3. Vulva
4. Vagina
5. Penis
6. Anus
42
Hepatitis B increases the risk of which type of cancer?
Hepatocellular carcinoma
43
Human Herpes Virus 8 increases the risk of which two types of cancer?
1. Kaposi sarcoma
| 2. Primary effusion lymphoma
44
Why was it previously thought that HIV caused Kaposi sarcoma?
There is a correlation between HIV and Kaposi sarcoma, but it was later found that this is because HIV increase the risk of Human Herpes Virus 8 so does not cause Kaposi sarcoma directly.
45
Human T lymphotrophic Virus-1 increases the risk of which type of cancer?
Adult T-cell leukaemia/lymphoma
46
Hepatitis C increases the risk of which two types of cancer?
1. Hepatocellular carcinoma
| 2. Non-Hodgkin lymphoma
47
Why does the inherited condition xeroderma pigmentosum increase the risk of skin cancer?
The DNA is less able to repair itself after mutation.
48
What source of non-ionising radiation increases the risk of skin cancer?
UV light (UVA and UVB)
49
Increased exposure to oestrogen increases the risk of which cancers?
Breast and endometrial cancers
50
Which factors in women lead to increased oestrogen exposure and therefore an increased risk of breast and endometrial cancers?
A higher number of menstrual cycles caused by:
1. Early menarche
2. Late menopause
3. Having fewer children
51
Anabolic steroids increase the risk of which type of cancer?
Hepatocellular carcinoma
52
The mycotoxin Aflatoxin B1 increases the risk of which type of cancer?
Hepatocellular carcinoma
53
The chlonorchis sinensis parasite increases the risk of which type of cancer?
Cholangiocarcinoma (bile duct)
54
The shistosoma parasite increases the risk of which type of cancer?
Bladder cancer
55
Which two practices have led to an increased incidence of oral cancer in India and south east Asia?
1. Reverse smoking (lit end held inside mouth, leading to thermal injury as well as exposure to smoke)
2. Chewing betal nut leaves, which are carcinogenic
56
Give 5 host factors that may influence an individual's risk of developing cancer
1. Race
2. Diet
3. Constitutional factors (age, sex etc.) that result in an inherited predisposition
4. Premalignant lesions (e.g. colonic polyps, cervical dysplasia, ulcerative colitis, undescended testis)
5. Transplacental exposures
57
Why do darker skinned individuals have a decreased risk of developing skin cancer?
Because of the protective effects of increased melanin
58
What type of skin cancer doesn't spread to other tissues?
Basal cell carcinoma
59
Why does leukaemia cause symptoms all over the body?
Because leukaemia cells are malignant versions of white blood cells, which circulate round the body
60
Name 5 types of cancer that commonly spread to the bones
1. Breast
2. Prostate
3. Lung
4. Thyroid
5. Kidney
61
How does Herceptin/trastuzumab infusion given over a one-year period increase the survival rate for patients with HER2 positive breast cancers?
It kills tiny tumours (micromets) in the body
62
What is a "microinvasive" carcinoma
A carcinoma which is technically invasive, but has not invaded very far and therefore has a low chance of spread and can therefore can be treated locally, e.g. squamous cell carcinoma of the cervix
63
How does ductal carcinoma in situ become an invasive ductal carcinoma?
When the basement membrane becomes compromised and malignant cells are able to move out of the duct and invade surrounding tissues
64
Why is it possible for a ductal carcinoma in situ to be cured with just a wide local excision?
The malignant cells are contained within the basement membrane and there are no lymphatic/blood vessels in the duct for the malignant cells to spread to.
65
What must DCIS cells produce in order to damage the basement membrane?
Enzymes to break down the basement membrane - proteases such as collagenase, cathepsin D, urokinase-type plasminogen activator.
66
Once the basement membrane of the duct is compromised, what else do DCIS cells require to become invasive?
Cell motility - they need to be able to physically move out of the duct
67
Give 3 ways in which cancer cells evade the host immune defence
1. Aggregation with platelets
2. Shedding of surface antigens (the antigens themselves are phagocytosed rather than the cell itself)
3. Adhesion to other tumour cells (the ones on the inside are protected)
68
Name 2 angiogenesis promoters
1. Vascular endothelial growth factor (VEGF)
| 2. Basic fibroblast growth factor (bFGF)
69
Name 3 angiogenesis inhibitors
1. Angiostatin
2. Endostatin
3. Vasculostatin
70
Why was it hoped that Avastin (bevacizumab) would stop tumour growth?
Avastin binds to VEGF-A and prevents binding to the receptor, thereby switching off the signal for blood vessels to grow.
However, it was not successful in preventing tumour growth.
71
Avastin was not successful in preventing tumour growth. What was it used for instead?
It can be used to treat macular degeneration caused by leaky blood vessels in the eye.
72
Why do sarcomas and some other cancers commonly metastasise to the lung?
They enter the circulatory system and providing they don't get stuck in the capillaries and are able to enter the venous circulation, end up in the lungs. Whilst some tumours will go on to invade the pulmonary veins and continue on to the left side of the heart where they can enter general circulation, many tumours are "filtered out" in the lungs.
73
Why is colon cancer most likely to spread to the liver?
The colon has a portal venous system, which drains straight into the liver. Therefore, the liver filters blood from the colon.
74
Besides colon cancer, which other cancers more commonly metastasise to the liver?
Stomach, pancreas and intestinal cancers
75
Name 5 cancers which commonly metastasise to bone
1. Prostate
2. Breast
3. Thyroid
4. Lung
5. Kidney
76
What are the two categories of bone metastases?
1. Lytic (cause bone breakdown)
| 2. Sclerotic (causes new bone formation)
77
How does the chemo drug vinblastine work?
Prevents cell division by binding to microtubules and preventing them from pulling the cell apart.
78
How does the chemo drug etoposide work?
It binds to topoisomerase II, which is required for DNA duplication --> DNA can't replicate, cell can't divide
79
What is the mechanism of action of ifosomide and cisplatin?
They bind to DNA and form cross links so that the DNA can't replicate
80
What is the disadvantage of conventional chemotherapy?
Conventional chemotherapy hits all dividing cells and is not selective for tumour cells. This means that cells which are supposed to be dividing are not, leading to side effects such as hair loss, myelosuppression and diarrhoea.
81
Which types of tumours does conventional chemotherapy work well against?
Fast dividing tumours, e.g. germ cell tumours of the testis, acute leukaemias, lymphomas, embryonal paediatric tumours and choriocarcinoma.
82
Apart from increased cell division, what other factor could increase tumour size?
A lack of apoptosis resulting in cells living longer
83
Name 3 techniques that can be used to compare cancerous tissue with normal tissue
1. Gene arrays
2. Proteomics
3. Tissue microarrays
84
How does cetuximab (Erbitux) work?
It is a monoclonal antibody against EGFR (epidermal growth factor receptor). It binds competitively to the extracellular domain of EGFR, thereby blocking the production of VEGF, interleukin 8 and bFGF
85
How does Herceptin work?
It is a HER2 monoclonal antibody - HER2 is activated when when HER2 proteins within the cellular membrane bump into each other. The antibody takes the protein into the cell, where it is endocytosed and broken down, resulting in much less HER2 on the surface and therefore a much lower chance of activation.
