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
What does a borderline classification mean?
Neoplasm defies precise classification.
List 9 features of benign neoplasms.
1) localised
2) non-invasive
3) slow growth rate
4) close resemblance to normal tissue
5) encapsulated
6) normal nuclear morphometry
7) necrosis rare
8) ulceration rare
9) exophytic growth on mucosal surfaces (into lumen)
List 5 ways benign neoplasms cause morbidity and morality.
1) destruction on adjacent structures —> pressure necrosis
2) obstruct flow
3) hormone production
4) transformation into malignant neoplasms (however most malignant neoplasms start as malignancies)
5) anxiety
List 9 features of malignant neoplasms.
1) ability to metastasise
2) invasive - destroy surrounding tissue
3) rapid growth rate
4) variable resemblance to normal tissue
5) poorly defined / irregular border - crab-like
6) hyperchromatic and pleomorphic nuclei
7) necrosis common
8) ulceration common
9) endophytic growth on mucosal surfaces (away from lumen)
List 7 ways malignant neoplasms cause morbidity and mortality.
1) destruction of adjacent tissue —> pressure necrosis
2) obstruct flow
3) hormone production
4) blood loss from ulcers
5) paraneoplastic effects - altered immune system response to a neoplasm
6) anxiety
7) pain - generally a late feature
Define histogenesis.
The specific cell of origin of a tumour. Specifies tumour type.
List 3 general origins of neoplasms.
1) epithelial cells
2) connective tissues
3) lymphoid/haemopoietic organs
What suffix do all neoplasms have?
-oma.
Nomenclature of benign neoplasm of non-glandular, non-secretory epithelium.
Papilloma, e.g. squamous cell papilloma.
Nomenclature of benign neoplasm of glandular or secretory epithelium.
Adenoma, e.g. thyroid adenoma.
Nomenclature of malignant neoplasm of epithelium.
Carcinoma, e.g. transitional cell carcinoma.
Nomenclature of malignant neoplasm of glandular or secretory epithelium.
Adenocarcinoma
Nomenclature of benign neoplasm of connective tissue.
1) prefix - cell of origin
2) suffix - -oma
List 6 examples of benign neoplasm of connective tissue.
1) lipoma - adipocyte
2) chrondroma - cartilage
3) osteoma - bone
4) angioma - vascular
5) rhabdomyoma - striated muscle
6) leiomyoma - smooth muscle
Nomenclature of malignant neoplasm of connective tissue.
1) prefix - cell of origin
2) suffix - -sarcoma
List 6 examples of malignant neoplasm of connective tissue.
1) liposarcoma - adipocytes
2) chrondrosarcoma - cartilage
3) osteosarcoma - bone
4) angiosarcoma - vascular
5) rhabdomyosarcoma - striated muscle
6) leimyosarcoma - smooth muscle
How are malignant neoplasms (carcinoma and sarcoma) further classified?
Further classified according to degree of differentiation.
How are malignant neoplasms classified based on differentiation? (I-III)
I - well differentiated —> similar to original tissue
II - moderately differentiated —> vaguely similar to original tissue
III - poorly differentiated —> dissimilar to original tissue
Define anaplastic.
Poorly differentiated cell of unknown origin.
List 3 exceptions to neoplasm -oma nomenclature.
1) granuloma - collection of epitheliod histiocytes
2) mycetoma - fungus
3) tuberculoma - TB mass
Define teratoma.
Neoplasm with cells from all 3 embryonic layers (mesoderm, endoderm, ectoderm).
Define metastasis.
Spread of malignant neoplasms.
List 3 factors that affect neoplasm invasion.
1) decreased cellular adhesion
2) secretion of proteolytic enzymes
3) abnormal/increased cellular motility
List the 3 possible routes of metastasis.
1) haematogenous
2) lymphatic
3) transcoelomic
Describe the process of metastasis of a neoplasm. (8)
1) break through basement membrane
2) break through extracellular matrix
3) enter vasculature (intravasation)
4) avoid detection (immune defence)
5) exit vasculature (extravasation)
6) break though extracellular matrix
7) break through basement membrane
8) grow and recruit blood vessels
List 3 ways metastatic neoplasms avoid detection.
1) aggregate with platelets
2) shed surface antigens
3) adhesion with other neoplastic cells —> inner cells are safe from immune cells
Where do metastatic neoplasm that invade veins generally end up?
Lungs.
Which neoplasms commonly metastasise to the lungs?
Sarcomas, generally via venous circulation.
Which neoplasms commonly metastasise to the liver?
Neoplasms from any organ that drains into the portal venous system, e.g. stomach.
Which neoplasms commonly metastasise to bones? (5)
1) prostate
2) breast
3) thyroid
4) lung
5) kidney
What type of malignant neoplasm invasion easier to recognise and why?
Carcinoma is easier than sarcomas. Basement membrane acts as a clear demarcation between tissue boundaries.
What method of metastasis do carcinomas prefer?
Lymphatic.
What method of metastasis do sarcomas prefer?
Haematogenous.
What does tumour grade assess?
Degree of abnormality of neoplasm.
List the 3 most important features to assessing tumour grade.
1) differentiation —> degree of resemblance to original tissue
2) mitotic activity
3) nuclear size (including hyperchromasia and pleomorphism)
What system is generally used to assess tumour stage?
TNM.
Describe the TNM system.
T (tumour) - primary tumour size —> varies based on organ. 1-4
N (node) - no. of lymph node groups containing metastases. 0-2
M (metastasis) - anatomical distance of metastases. 0-2
What does tumour stage assess?
Neoplasm metastasis.
