Cancer Flashcards
Define oncogenesis.
Transformation of normal cells to neoplastic cells through permanent genetic alterations or mutation.
Define carcinogenesis.
Transformation of normal cells to malignant neoplastic cells through permanent genetic alterations or mutations.
Define carcinogenic.
Cancer causing.
Define oncogenic.
Tumour causing.
Define mutagenic.
Acts on DNA.
List the 5 broad classes of carcinogens.
1) chemical
2) viral
3) biological agent
4) radiation (ionising and non-ionising)
5) miscellaneous
List 2 features of chemical carcinogens.
1) no common structural features
2) most require metabolic conversion (pro-carcinogen —> ultimate carcinogen)
Describe metabolic conversion of chemical carcinogens. (3)
1) pro-carcinogens are converted to ultimate carcinogens by enzymes
2) enzyme may be confined to a certain organ —> neoplasm could be organ-specific
3) enzyme may by ubiquitous —> neoplasm could occur systemically
List 3 examples of biological agent carcinogens.
1) hormones, e.g. oestrogen in mammary cancer
2) mycotoxins, e.g. aflatoxin B1 in heptocellular carcinoma
3) parasites, e.g. shistosoma in bladder cancer
List 2 examples of miscellaneous carcinogens.
1) asbestos
2) metals, e.g. lead or arsenic
List 4 host factors affecting neoplasm formation.
1) constitutional factors, e.g. age, gender, race
2) diet
3) premalignant lesions - local abnormality associates with increased risk of malignancy
4) transplacental exposure, e.g. diethylsteboestrol —> vaginal cancer
Define tumour.
Any abnormal swelling.
List 4 types of tumour.
1) neoplasm
2) inflammation
3) hypertrophy
4) hyperplasia
Define lesion.
Localised abnormality.
Define neoplasm.
A lesion resulting from autonomous abnormal growth of cells, which persist after initiating stimulus is removed.
List the 3 defining features of a neoplasm.
1) autonomous
2) abnormal
3) persistent
List the 2 components of a neoplasm.
1) neoplastic cells
2) stroma
List 3 features of neoplastic cells.
1) usually monoclonal (single ancestral cell)
2) growth pattern related to parent cell
3) synthetic activity related to parent cell
Describe the stroma.
Network of cells that support neoplastic cells.
List 3 ways stroma support neoplastic cells
1) connective tissue framework
2) mechanical support
3) nutrition
What is essential in neoplasm growth?
Vascularisation.
From what size onwards do neoplasms need vascularisation?
Greater than 2mm diameter.
What is the central necrosis?
Necrosis of the centre of malignant neoplastic tissue, as it grows faster than it can recruit blood vessels.
List 2 reasons to classify neoplasms.
1) determine appropriate treatment
2) provide prognostic information
List 2 methods of classifying neoplasms.
1) behavioural: benign/borderline/malignant
2) histogenetic: cell of origin