Session 1 - General Overview (Updated & Accurate) Flashcards
What are three distinguishing features of cancer?
- Uncontrolled growth
- Invasion into adjacent tissues
- A tendency to undergo metastasis
What is metastasis?
Tumour cells which spread from site of origin to non-contiguous locations via a variety of mechanisms.
What differentiates benign from malignant tumours?
Benign tumours, unlike malignant tumours, do not grow uncontrollably, invade locally or metastasize.
What is a carcinoma?
A cancer which arises from epithelial cells
What is a sarcoma?
Arise from connective tissue such as bone, cartilage, fat, connective tissue and muscle.
What is a lymphoma/leukaemia?
What is a lymphoma/leukaemia?
What is a germ cell tumour?
Cancers derived from pluripotent cells, most often presenting in the testicle or the ovary.
What is a blastoma?
Cancers derived from immature “precursor” cells or embryonic tissue, which are common in children.
What are the biggest contributing factors to cancer?
90-95% of cancer cases due to environmental factors, with only 10% due to genetics
Give three causes of cancer
- Tobacco
- Diet alcohol
- Obesity
- Lack of physical activity
- Infections
- Radiation
- Hormones
- Pollutants
What is an environmental mutation called?
somatic mutation
What is a genetic mutation?
Hereditary mutations
What are local symptoms of cancer?
Restricted to the site of cancer
- Lumps or swellings
- Haemorrhage
- Ulceration
- Pain
What are metastatic symptoms of cancer?
due to distant effects of the cancer that are not related to direct or metastatic spread.
- Weight loss (poor appetite)
- Fatigue
- Excessive sweating (night sweats)
- Anaemia (low RBC)
Give five ways cancer can be detected
- Imaging
- Endoscopy
- Tissue samples – Histopathology
- Tests of blood and other samples
- Cancer Screening
Give six ways we can treat cancer
- Surgery
- Radiotherapy
- Chemotherapy
- Hormone therapy
- Immunotherapy
- Gene therapy
Give six hallmarks of cancer
1) Sandy – Self-sufficient
2) Beaches – Angiogenesis
3) Rectum – Resistant to anti-growth
4) Gets – Grows indefinitely
5) Invaded – invades into surrounding tissue
6) Regularly – Resists cell death
Why don’t benign tumours grow uncontrollably?
Benign tumours grow slowly, and do not invade into tissues in the same was as a malignant tumour. By definition rarely grow uncontrollably.
How does lung cancer produce ACTH in para-neoplastic syndrome?
Small cell lung cancer originates from neuroendocrine cells in the bronchus called feyrter cells, which can product ACTH.
What does polygenic mean?
Polygenic diseases are conditions influenced by multiple genes.
What is a blastoma?
A cell formed from multipotent blast cells in children.
What kind of gene is BRCA1?
BRCA1 is a tumour suppressor gene, and its absence (due to mutation) can increase the likelihood of women developing breast cancer.
Outline the stages of carcinogenesis
Initiation -> Promotion -> Progression
What is initiation?
DNA damage caused by mutagens
Give four examples of initiators
Chemicals
Radiation
Infections
Replication errors
What genes do mutagens target?
Oncogenes and Tumour Suppressor Genes
What effect do mutagens have on tumour supressor genes and oncogenes?
Translocation and up-regulation of oncogenes, while inactivating the tumor supressore genes.
What is the difference between direct acting carcinogens and procarcinogens?
Direct acting carcinogens bind to DNA directly, with examples including alkylating and acylating agents, along with cytotoxic drugs which encourage increased replication. Procarcinogens on the other hand require metabolism within the body before they can damage DNA – a key example being polycyclic aromatic hydrocarbons.
Give five ways in which genes mutate
Alteration of bases • Strand break • Base oxidation • Deletion of bases • Deletion of chromosome fragments
Give two ways in which genes are protected
repair mechanisms, such as mismatch and excision repair, and regulators such as p53.
Name four types of promotoers, giving examples of each
- Chemical promoters – Phorbol esters and phenols
- Hormones – Oestrogen in breast cancer
- Inflammation – Chronic irritation, endoparasites and bacterial infection
- Microbial Infection – Helicobacter pylori
Give three ways in which cell signalling is important in cancer
- cell receptor expression goes up or down
- receptors activate themselves
- inhibitory proteins are downregulated
Give an example of food causing cancer
, consumption of over-cooked red meat can increase levels of the carcinogen heterocyclic amine. This is caused by the combination of phenylalanine, creatine and heat in the animal muscle during the cooking process. HA is then metabolised by the liver to genotoxic metabolites.
What is chemoprevention?
the prevention of cancer by the use of pharmacological agents that inhibit or reverse the process of carcinogenesis
What is the difference between primary, secondary and tertiary patient groups in treatment?
primary (general pop), secondary (early stage + familial risk) and tertiary stage (increased-risk patients).
How does aspirin prevent cancer?
Inhibits cox-1, preventing inflammation and thus promotion of cells.
What does tamoxifen do?
Competitively competes with oestrogen at receptor level, preventing hormonal promotion of cancer
Give a dietary chemopreventer
Turmeric
How does Schistosomiasis cause bladder cancer?
Chronic inflammation causes by the schistome nematode may cause an increased cancer risk, by producing oxygen radicals which damage DNA of bladder cells, and also allow the formation of carcinogenic N-nitrosamines.
Give three environmental categories of mutation
- Ultimate carcinogens bind to DNA & alter sequence
- Ionising radiation / UV – strand breaks, cross links
- DNA translocated to transcriptionally active regions
Give four intracellular categories of mutation
- Misinterpretation of code
- Polymerase slippage / base
- Malalignment
- Ineffective repair
Give two examples of direct acting carcinogens
Alkylating and acylating agents - dimethylsulphate and chlorambucil
Weak Carcinogens - Lymphoma and Leukaemia
Give two examples of procarcinogens
Polycyclic aromatic hydrocarbons - Bezaanthracene
- Benzopyrene
Combustion of organic compounds
