Tumour Pathology Flashcards
Describe the balance between cell proliferation and apoptosis in cancer.
In cancer, accumulation of proliferating cells (cell survival/proliferation»_space; cell death)
Is the level of cell proliferation the same everywhere in the body ?
No.
Lots of proliferation in hair and nails, very little or none in neurons
Define the term neoplasm.
A new and abnormal growth of tissue in a part of the body, especially as a characteristic of cancer.
Describe the type of cells making up tumours.
- Neoplastic cells, which are present in stroma
2. Stroma (connective tissue, blood vessels, inflammatory cells)
Why are tumours said to be autonomous ?
Because response to physiological stimuli lost or abnormal, allowing unregulated growth
What is the main risk factor for cancer ? Why is that ?
Age
Because long time for most cancers to grow + for cumulative changes in tumour cells to have clinical effects
Which kind of tissue do the most common kinds of cancer arise in ?
Epithelial Tissues
Distinguish between the most common cancers in men and women.
MEN
- Prostate
- Lung
- Large bowel
- Bladder
WOMEN
- Breast
- Large bowel
- Lung
- Ovary
Why are cancers (i.e. cells proliferating too much) a problem ?
Because cancer cells do not obey strong borders, infiltrate other areas and cause chaos in surrounding material
What are the hallmarks of cancer ?
- Evading apoptosis
- Self-sufficiency in growth signals (Must able to grow autonomously without signals, because will get signals telling it to stop growing)
- Insensitivity to anti-growth signals
- Tissue invasion and metastasis
- Limitless replicative potential (Molecular clock inside normal cells only allow limited amount of cell cycles which is programmed at the end of chromosomes (telomeres). Cancer cells extend telomeres by activating telomerase allowing them to have limitless numbers of cell cycle).
- Sustained angiogenesis (to get supply of oxygen and nutrients)
Describe the main events in cancer timeline, including the diagnosis.
- Initiation/Promotion (some DNA event in some cell)
- Growth
- Diagnosis/Excision (of some bit of cancer tissue. Biopsy it to reveal which kind of cancer, course of treatment, and
prognosis) - Cure/relapse/metastasis/death
Distinguish malignant from benign tumours.
BENIGN * Well circumscribed * Slow growth * No necrosis * Non-invasive * No metastasis -Intact surface -Exophytic growth -Homogeneous cut surface -Circumscribed or encapsulated edge (does not move to the layer down) * Resemble tissue of origin * Well differentiated * Minimal nuclear pleomorphism * Mitotic figures normal
MALIGNANT
* Poorly circumscribed
* Rapid growth
* Often necrotic
* Invasive
* Metastasis
-Heterogeneous cut surface due to necrosis
-Ulcerated surface
-Endophytic growth (Growing down into next tissue layer)
-Vascular permeation
-Irregular infiltrative edge
* Variable resemblance to tissue of origin
* Variable differentiation (Some cells look like tissue or origin, some do not)
* Variable pleomorphism may be anaplastic
* Mitotic figures abnormal
* High nucleo-cytoplasmic ratio
* Nuclear hyperchromasia (increase in chromatin in cell nuclei)
* Nuclear pleomorphism (variability in the size and shape of cells and/or their nuclei)
* Abnormal chromatin structure
What are possible clinical effects of benign tumours ?
Do NOT invade or metastasise BUT not always clinically benign! (may still cause problems)
1) Space occupying effects
• Obstruction
• Epilepsy (when in the brain)
• Conduction abnormalities
2) Haemorrhage (if in blood supply)
• Pulmonary
• Gastrointestinal
3) Hormone production
• Pituitary
• Adrenal
• Endocrine pancreas
How do malignant tumours spread ?
- Directly invade locally
- Via the lymphatics
- Via the bloodstream (haematological)
- Through body cavities (transcoelomic)
Do all tumours metastasise in the same manner/ with the same distribution ? Explain, giving examples.
No, some of tumour cells have a preference about secondary site where want to grow (preferentially growing there).
Prostate –> bone
Lung –> brain, adrenals
Breast –> lung, liver, bone, brain
Ovary –> peritoneal cavity
Identify the types of tumours structurally. State whether each kind tends to be benign or malignant.
Sessile: More bengign
E.g. skin cancer
Pedunculated: More benign
E.g. colorectal cancer
Papillary: More benign
Fungating: More malignant
Ulcerated: More malignant
Annular: grows centripetally
E.g. within vessels
Define dysplasia.
Presence of cells of an abnormal type within a tissue, which may signify a stage preceding the development of cancer.
What is the nomenclature for Benign connective tissue (mesenchymal) tumours ?
Begin with term denoting cell of origin e.g. lipoma (adipocytes)
Give examples of benign mesenchymal tumours.
Give examples of malignant mesenchymal tumours.
What is an experiment which shows that many tumours have a clonal origin ?
- Gene for Glucose 6 phosphate dehydrogenase (G-6PD) is on X chromosome
- Two forms of the enzyme which can be separated using chromotography (A and B forms)
- For women with particular cancer, can look into tissue to see if A form or B form. Since X inactivation (one of the two X chromosomes randomly switched off in the cells, Lyon inactivation hypothesis), within particular cell, should only express one or the other
- Using chromatography, may separate the two forms of the enzyme in body tissues
- Normal tissue, express both, so is a 50 : 50 mixture of both enzyme markers (assuming that one parent has XA and the other has XB), 50% cells express A and 50% express B, child will be heterozygous (but individual cells 100% one or the other)
- If the tumour arises from a single cell i.e. is clonal in origin, then all the Tumour cells will have the same enzyme marker (because all origin from a single cell)
